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TODD RUZICKA
TODD RUZICKA,
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Experience:  Service Consultant at Main Motor Chevrolet
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98 Chevrolet C1500 Cheyenne 5.7 Door locks not working

Customer Question

98 Chevrolet C1500 Cheyenne 5.7
Door locks not working
Already tested the controls and they are sending out voltage but the voltage is not arriving at the door locks motors. I assume it was the door lock relay but I have already removed the dash board and could not find the relay anywhere
Submitted: 6 months ago.
Category: Chevy
Expert:  adamfeather replied 6 months ago.

Hello, my name is ***** ***** I'll be happy to assist you today. I have an associates degree in automotive technology, ASE certified with 15 years in the field. I'm sorry to hear your having trouble finding the relay. I'm going to see if I can find a decent picture for you and will be back ASAP.

Thanks,

Adam

Customer: replied 6 months ago.
ok be sure that its specific to the cheyenne submodel because I also have a c1500 silverado and I was able to find the relay on it. and its located in the same spot that its supposed to be located in the cheyenne but Its not there.
Customer: replied 6 months ago.
thank you
Expert:  adamfeather replied 6 months ago.
Ok found it. Hopefully this helps find the problem. I have also seen instances where the wiring gets rubbed through or broken and causes the breaker to burn out. Be sure to look around closely while you have the dash out. Maybe leave it out until your sure you find the problem. Don't hesitate if there is anything I can do for you!
Thanks,
Adam
Customer: replied 6 months ago.
Yeah thats the same picture I had. This truck does not have the relay in that place. My other truck does though. Is there an alternate location for it?
Customer: replied 6 months ago.
This is the Vin for my vehicle 1GCEC14R4WZ151858
Expert:  adamfeather replied 6 months ago.
Ok. Sorry about that. I used the Cheyenne for sure but obviously somethings different. Let me looks a little further and I'll get back ASAP.
Adam
Customer: replied 6 months ago.
Ok Ill take some pictures and send them your way so you can see what I mean
Customer: replied 6 months ago.
ok so there is the pictures both are my trucks and I am pointing the camera at the same area in fact you can see the ac actuator on both pictures but the cheyenne doesn't have the relay in the same place. I also looked around there to make sure that the relay had not been cut off or anything like that but there are no cut wires hanging there at all.
Expert:  adamfeather replied 6 months ago.
Ok I see what you mean.... I just now read an article and someone mentioned the relay sometimes being above the accelerator pedal?? Check around that area and let me know. I have a pinout if you need showing the wire colors but it looks like you can cheat off your other truck it should look the same. Let me know and I'll keep helping if you don't find it there.
Thanks
Adam
Expert:  adamfeather replied 6 months ago.
This is a bit of the article.Customer Concern: All the door locks want to cycle but do not lock or unlock any of the doors.
Average Reported Mileage: 125087
Tests/Procedures: 1. Access an actuator and check for good powers and grounds on the Gray and Tan wires.2. If ok, replace the actuator.3. If all actuators have failed, replace the relay located above the accelerator pedal.
Tech Tips: Check for a history of a dead battery from the relay sticking on causing the actuators to all fail.
Customer: replied 6 months ago.
Ok so I went to look all around the pedal. I did find a connector near the top but the relay was not there and the wires going into the connector did not match the ones from my other truck... I dont think this it the location for it. Could you also send me a wiring diagram of the power locks specific to the cheyenne I want to compare it to the diagrams I got and make sure I didnt miss anything
Expert:  adamfeather replied 6 months ago.
I sure can. I will send all I can within the next few mins. However keep in mind even the dealer diagrams I have are general to the 1500 series chassis so they even show as if it has 4 doors. They do say in the diagram (4 door only) so you know it may not apply. Hang In there I'll start getting them together.
Expert:  adamfeather replied 6 months ago.
Bare with me I'm just going to send things I find may help as I come across them.
The power door lock system incorporates door lock switches on both front doors and on the RH D-pillar, door lock motors in all passenger doors and in the RR cargo door, a door lock relay and a door lock control module.Power for the door lock switches and the door lock control module is supplied from the CIG LTR fuse 13 through CKT 640 (ORN). Power for the door lock relay is supplied from the PWR ACCY circuit breaker through CKT 540 (ORN). Ground for the door lock relay is supplied from G202 through CKT 150 (BLK) and ground for the door lock control module is supplied from G400 through CKT 150 (BLK).The door lock motors are reversible and both sides are connected to the normally closed contacts of the door lock relay. Those contacts of the relay are connected to G202. When any of the door lock switches are placed in the lock position, voltage is supplied through CKT 195 (LT BLU) to the relay lock coil. Since the other side of the lock coil is connected to ground, the coil is energized and it pulls the lock contacts closed. Voltage is then supplied through CKT 295 (GRY) to all the door lock motors and the doors lock. The unlock function operates in much the same manner except that when any of the switches are placed in the unlock position, voltage is supplied through CKT 194 (WHT) to the unlock coil of the relay and CKT 294 (TAN) supplies voltage to the apposite side of the door lock motor and the doors unlock.Door Lock Control Module DescriptionThe door lock control module is used on vehicles equipped with cargo doors. The purpose of the module is to lock the cargo doors after a lock cycle has been commanded from any of the door lock switches with the cargo doors open. When the RH cargo door is open, the module receives a ground signal from the closed contacts of the rear door jamb switch on CKT 1897 (ORN/BLK) to G400. When a lock command is received, the module retains this input until it receives an open input from the rear door jamb switch. Then the module sends a lock command through CKT 194 (WHT) to the door lock relay and the doors lock.
Expert:  adamfeather replied 6 months ago.
More to come
Expert:  adamfeather replied 6 months ago.
I have a connector view coming too. Sorry I have to type something to attach the image...
Expert:  adamfeather replied 6 months ago.
Connector view
Expert:  adamfeather replied 6 months ago.
Let me know if there is anything else I can do to help. I have troubleshooting tree I can send but they can be difficult and tough to navigate through. If you know you have power out of the switches make sure it's getting to the relay. Then out of the relay to the actuators. Worse case follow the light blue wire and the white wire coming out of the switches. You may have to peel open the harness every couple feet or at the intersections with other harness to see which route they go. Hopefully this helps get to the bottom of it!
Customer: replied 6 months ago.
Will have to continue tomorrow morning. Had to leave already
Expert:  adamfeather replied 6 months ago.

OK no problem. It's hard to be available at all times as I am a private contractor but I promise I will respond further as soon as I see your response.

Thanks,

Adam

Customer: replied 6 months ago.
sorry I didnt get a chance to work on the truck over the weekend. I will start working on it right now. Let me read through your information
Customer: replied 6 months ago.
I am still running into the same trouble after reading you info. I already tested the voltages at the door lock module. It all seems in place, in fact I can go do it again and write down the voltages for each of the wires coming out of the module. Problem is that I cant locate the relay anywhere I tried taking off the entire dash board and following the wires to the relay. But it got to the point where I had to remove even more parts in order to get access to the wires so thats why I decided to ask here if you could help me find the relay or if there is something else for this models. Because the normal location where the relay is for c1500 does not apply for this truck
Expert:  adamfeather replied 6 months ago.
Ok. Very sorry we haven't figured it out. I'm not back at my computer until around 6pm est.
I'll check into it 1 more time. If I come up empty I apologize I may have to opt out and see if there is another expert that may have a first hand experience like this. I'll be In touch.
Adam
Customer: replied 6 months ago.
Darn that doesnt really work with my schedule, By 6 I wont have much time left over to work on the truck.
Customer: replied 6 months ago.
Not that I dont think you cant figure out the location, I appreciate the help you provided so far but I would like to get this moving along sooner, do you think you could opt out so someone one else available could help me continue sooner
Customer: replied 6 months ago.
Did you get my last message?
Expert:  adamfeather replied 6 months ago.

I'm very sorry I didn't opt out sooner for you! I did check some old shop manuals at my shop and they are all showing what we already know. (the wrong location). I will OPT out now and if i come up with anything different I will still try to help! Hopefully one of gets this resolved for you.

Adam

Expert:  Don 'Mo Lurch' replied 6 months ago.

IF this is a 1998 Cheyenne & this has Factory Power Door Locks, you likely do NOT have a Door Lock Relay.......
The circuit would be "Reversal Rest At Ground"
IF there is Voltage + on the ORANGE wire at the Driver & Passenger Switch
Pressing LOCK should show Voltage + out of the Switch on the LIGHT BLUE wire (driver switch) & GRAY wire (passenger switch)
Does it??

Customer: replied 6 months ago.
Hello thank you for responding... Thank god so there is no relay then... ok... so there is voltage when I press both the drive and passenger side buttons to lock or unlock the truck... however when I check for voltage and the lock motors there is no voltage there.
Customer: replied 6 months ago.
To answer your question there is voltage on the orange wire at all times. and there is voltage on the light blue wire and gray wire when pressing lock
Customer: replied 6 months ago.
There is however no voltage at the gray or tan wires directly on the door lock motors
Expert:  Don 'Mo Lurch' replied 6 months ago.

As posted the Circuit is "Reversal Rest at Ground"
Meaning:
When Lock is pushed the LIGHT BLUE wire (driver switch) & GRAY wire (passenger switch) will have Voltage +
The WHITE wire on Driver & Passenger Switch will have Ground -
Or the TAN wire at the Door Lock Motor will have Ground -
.

When UNLOCK is pushed, the LIGHT BLUE wire (driver switch) & GRAY wire (passenger switch) will have Ground -
The WHITE wire on Driver & Passenger Switch will have Voltage +

Or the TAN wire at the Door Lock Motor will have Voltage +

.

This is how the Voltage + & Ground - works the Door Lock Motors, by "reversing" the Voltage + & Ground -
Be sure you have a good Ground - on the BLACK wire of the Driver Switch
Here is Schematic
Click Attachment Below

Expert:  Don 'Mo Lurch' replied 6 months ago.

The Ground "G202" BLACK wire is to the Left of the PCM at rear of dash on Firewall inside

Customer: replied 6 months ago.
Ok Im checking everything on the diagram right now. Ill write voltages and grounds on it and send it back to you
Expert:  Don 'Mo Lurch' replied 6 months ago.

sorry......lost internet

thanks, ***** ***** on for apprx 1 more hour, then on tomorrow

Customer: replied 6 months ago.
ok sending the diagram back right now
Expert:  Don 'Mo Lurch' replied 6 months ago.

thanks

Customer: replied 6 months ago.
ok so what stands out to me is the passenger side switch only throws out 1.12 volts when the unlock or lock button is pressed. this happens on all the wires on the passenger side (tan white ltblue and gray)...
Customer: replied 6 months ago.
here is the diagram
Expert:  Don 'Mo Lurch' replied 6 months ago.

But the ORANGE wire has at least 11.5 volts DC?

Customer: replied 6 months ago.
yeah
passenger side has
11.68 volts on orange wire
lt blue and white wires have 11.56 of ground
but when lock or unlock is pressed all the wires get 1.12 volts for some reason
Expert:  Don 'Mo Lurch' replied 6 months ago.

Doors UNLOCKED:
With Passenger Lock pressed ...what happens if you BRIEFLY "jumper" a Ground - wire to the TAN wire of the Passenger Switch?

Customer: replied 6 months ago.
ok with the door unlocked i pressed the lock button while grounding the tan wire... i tried grounding it with a good ground on the truck as well as with the white wire. nothing happened...
Customer: replied 6 months ago.
one more thing of note is that the orange wire gets pretty warm
Customer: replied 6 months ago.
I own another truck that has the same kind of controls and tried swapping the passenger side switch but it changed nothing
Expert:  Don 'Mo Lurch' replied 6 months ago.

IF you were to Unplug both switches & jumper the GRAY wire at the Passenger Switch with Voltage + & Jumper the TAN wire with Ground-, the Door Lock Motors should respond

Customer: replied 6 months ago.
quick question about the grey wire... on the switches there is not really a grey wire the closes color to it is a dark brown wire and I assumed that its the grew wire... however the wire that goes to the lock motors is actually grey and looks nothing like the one at the switch
Expert:  Don 'Mo Lurch' replied 6 months ago.

are there letters on the plugs that correspond to the wire colors..........

Customer: replied 6 months ago.
let me check
Customer: replied 6 months ago.
it goes a b c d e f g .....
Customer: replied 6 months ago.
here is what the wires look like
Expert:  Don 'Mo Lurch' replied 6 months ago.

thanks..............
I may have wasted your time.........
When you have "both plugs connected"......Press Lock or Unlock, do you here any "clicking" under the dash, as that is a Plug for the Relay version.
The "click" will be faint, if at all

Customer: replied 6 months ago.
No clicking there is no relay. I have searched everywhere for it. Everyone tells me the relay is in the same spot. My other truck has the relay in the location that this trucks are supposed to have it
Expert:  Don 'Mo Lurch' replied 6 months ago.

the problem with this year is there were 3 types
The Circuit I provided
The circuit for the Relay under Driver Dash
The circuit for 2 Relays in the Fuse Panel
The Reversal Rest At Ground, as I posted is still correct for the circuit I posted & the Relay under the Dash
The BROWN wire is for Park Lamp feed for the Lighted Switches
.

I saw the picture you posted under the dash & I have seen the Relay mounted above the Steering Column area. Not where it typically is.
At this point, after seeing the Plug you have, with the Door Switches in "neutral" position, the ORANGE wire is Voltage +, WHITE wire is Ground -, the LIGHT BLUE is Ground -, the TAN wire is Ground -, the BROWN wire is Park Lamp feed +, but I show nothing for the DARK BLUE, which I assume is Ground -
You may want to see what wires come from the Door Lock Motors to the Switch.
Unplug both switches
Then test each Door Lock Motor by jumpering the 2 wires from each Door Lock Motor at the Switch Plug to see if the Door Lock Motor responds
Then reverse the Jumpers to see if the Door Lock Motors respond the opposite way
I have GM Service Manual & cannot see the 2 DARK BLUE wires goung to either plug
Will have to research in morning, but I am truly sorry for the issue..........

Will post back
thanks

Customer: replied 6 months ago.
One thing to consider is that half of those wires you are seeing are from the power windows
Customer: replied 6 months ago.
you think there is actually 2 relays then?
Expert:  Don 'Mo Lurch' replied 6 months ago.

I have the V.I.N. & will need to have a look on which circuit it is........
I still believe it is a non relay / Reversal Rest At Ground type, but the GM diagrams I have here are not showing the complete circuit......
Typical for those years.........Will try to get the diagrams first thing

thanks

Expert:  Don 'Mo Lurch' replied 6 months ago.

are you sure the picture of the Plug you posted is for the Door Locks?

Customer: replied 6 months ago.
sir. But the door locks and power windows all plug jn the same place
Expert:  Don 'Mo Lurch' replied 6 months ago.

yes .....I understand.........thanks

Customer: replied 6 months ago.
I verified this by clicking the power windows and checking what wires had voltage. Also clicking the locks and seeing what wires had voltage
Expert:  Don 'Mo Lurch' replied 6 months ago.

ok.......will post back as soon as I get the correct diagrams

thanks

Expert:  Don 'Mo Lurch' replied 6 months ago.

will have to pass on this, as GM only has those same diagrams as posted........
at this point, I would trace harness from driver door, into dash & trace across dash to passenger door
IF there is NO Relay branching off at the point the diagram shows, then it could have been moved or someone has rewired
Being Internet, this is very difficult without being "hands on".........
Will OPT OUT & RELIST

Please do not respond to this, as it will Lock Question

Customer: replied 6 months ago.
hello its been close to 4 hours and no one has responded yet. I have to respond to you even though you say it will lock the question, no one is replying back yet.
Customer: replied 6 months ago.
last thing I did was unplug the lock motors from both doors in case the reason no voltage was leaving the switch on the passenger side was because one of the motors was burnt or shorting out. After unplugging the motors however there was no change. I believe we are very close to the source of the problem
Customer: replied 6 months ago.
Hello?
Customer: replied 6 months ago.
Anyone?
Customer: replied 6 months ago.
Id like to continue with this diagnostic
Customer: replied 6 months ago.
Well this is interesting... So does this mean this sesion is over?
Customer: replied 6 months ago.
could someone please answer I need to get this done soon
Customer: replied 6 months ago.
hey guys its been 24 hours... can i talk to a moderator or anyone?
Customer: replied 6 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 6 months ago.
Don 'Mo Lurch&#039 I pulled this relay from the truck 15150325 from the top of the steering wheel. could it be that this is the relay that controls the door locks?
Expert:  Tool Hut replied 6 months ago.

Hi, My Name is ***** ***** for posting your question to just answer. I am a independent contractor for just answer. ASE Certified Master Auto Technician with 20 years experience. I am confident we can resolve your problem together.Please remember I don't know your skill level. I can't see, smell, hear, or touch the vehicle. It may take a few back and forth replies to get to a satisfactory resolution.There will probably be some equipment needed for a proper diagnosis. If you are not comfortable with this or do not have any test equipment please let me know ASAP. I also give you all of the information you may need in good faith expecting a positive rating. I am not compensated for my time until you leave a positive rating. Your rating should be based on the service you received.

Do you still need help? Do you have a test light instead of the meter?

Expert:  Tool Hut replied 6 months ago.

the relay you pulled is a lamp control relay

Customer: replied 6 months ago.
I do have a test light... I know that the relay I pulled is for the lamp control relay but if you read through this page for that parthttp://www.wholesalegmpartsonline.com/products/GMC/MODULE-Instrument-PanelInterior-Lamp-Switch/2717447/15150325.htmlthere is parts where unless im understanding incorrectly it says that it is also used for the lock controls
I will post a picture with the area i am talking about circled
Customer: replied 6 months ago.
here is the picture
Customer: replied 6 months ago.
I have also read a few forums where people where trying to switch their c1500 from just power locks to the control power locks and they refered to that relay as the one that needed to be replace. I might be wrong, all I am saying is if you could look deeper into that relay to see if maybe it is the one I am looking for its just that the relay is normally also used for the lamp controls.
Expert:  Tool Hut replied 6 months ago.

OK. It could be the relay. Lets start back at the door. Where the door opens there is a black tube. If you push it into either the door or the cab you can inspect the wires, I strongly suspect you have broken wires in there. Sometimes it is easier to disconnect inside cab and pull wires into door.

Customer: replied 6 months ago.
I ran a continuity test from the light blue wire on the driver side to the passenger side and it tested good. I did the same for the white wire tested good as well. I also tested the ground wires and they get good ground. problem is when i press the lock or unlock button on the passenger side only 1.2 volts leaves through the tan wire and the other wire
Customer: replied 6 months ago.
ok so i replaced the relay 15150325 with no luck.
I got some lock switches from a different truck that I know are in working condtions and tested mine on the other truck. My switches are in working conditions as well. So I have crossed the switches out because they cant be the problem. there has to be a relay somewhere that I am missing
Customer: replied 6 months ago.
Update: so I checked and the grey wire and tan wire that connect to the motors are not grounded. anyone know where this wires are grounded to?
Customer: replied 6 months ago.
what is ground distribution cell 14? I found the ground location g202
Expert:  Don 'Mo Lurch' replied 6 months ago.

Update: so I checked and the grey wire and tan wire that connect to the motors are not grounded. anyone know where this wires are grounded to?

.

I am sorry no one has responded, but this question has a lot of issues
I posted earlier that this is a "Reversal Rest At Ground Circuit"
Meaning:
There are "TWO" wires at the Door Lock Actuator / Motor
When the Switch is pressed to LOCK:
One wire will have Voltage +
One wire will have Ground-
Then, when the Switch is pressed to UNLOCK:
The wire that had Voltage + should now have Ground -
The wire that had Ground - now should have Voltage +
So to answer your last "Update",
At the Door Lock Actuator / Motor:
IF the Gray wire has Voltage + & the TAN wire has Ground -
Then the Actuator should move one way or the other
Then if you switch the wires, the Door Lock Actuator / Motor should move the other way
IF it does NOT, replace the Actuator
I cannot continue with this, as you have not followed thru with my suggestions & hands on cannot be done

Customer: replied 6 months ago.
I will follow through with your suggestions whats the first suggestion?
I took off the both switches and both motors and tested them on my other truck all worked fine.
Customer: replied 6 months ago.
I checked my other truck to see how the voltages and grounds work. when nothing is being pressed on my other truck both the grey and tan wires have ground going to them.
on the cheyenne it shows me that there is no ground going to either wire right now. So I found ground G202 to see if it was connected and the ground seemed fine.
Customer: replied 6 months ago.
Im pretty good at following instructions if you tell me what to do Ill give you the results back in a couple minutes
Expert:  Don 'Mo Lurch' replied 6 months ago.

I checked my other truck to see how the voltages and grounds work. when nothing is being pressed on my other truck both the grey and tan wires have ground going to them.

.

That is correct, as I explained a few days ago...
Circuit is "Reversal "Rest at Ground"

.

I believe there is a Relay somewhere in the truck
may not be where it is supposed to be, but by the way you have described it in all your posts, which I have read a number of times, this appears to be Relay driven

.

I would trace harness from driver door, into dash & trace across dash to passenger door

IF there is NO Relay branching off at the point the diagram shows, then it could have been moved or someone has rewired

.

Customer: replied 6 months ago.
I just took off the entire dashboard about two hours ago and traced the wires from one door to the other. no relay anywhere.
Im not saying you were wrong about the reversal rest at ground. Im just saying that neither of the wires is getting ground right now on the faulty truck. What should I do next? I have pictures of the entire harness from one side to the other with no relay anywhere.
Customer: replied 6 months ago.
well it seems like no one is willing to tackle this job anymore. If thats the case I was left with the same knowledge I already had coming in. I would like to get a refund unless someone can help me figure this out
Customer: replied 5 months ago.
Alright well if no one can answer that question can you at least help me figure out whats wrong with the instrument cluster on my 2010 ford f150 XL Vin:1FTNF1EV4AKE47242.
Everything works properly on the truck except my instrument cluster doesn't power up: no speedometer rpms etc.... outside lights work everything else works but no power to instrument cluster. If there is a wiring diagram for the cluster it would help a lot.
Customer: replied 5 months ago.
well looks like I wont get an answer on anything Id like to get my money back since the services i paid for were not provided
Expert:  TODD RUZICKA replied 5 months ago.

Hi and thank you for the question, I'm sorry you are having this issue. I'll do my best to help you ok. Let me look up the schematics and I'll be right back with you...