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Shawn
Shawn, GMC Mechanic
Category: GM
Satisfied Customers: 289
Experience:  I have been repairing cars for 20 years.
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I have a 2005 Silverado with a 5.3. I turn the switch and

Customer Question

I have a 2005 Silverado with a 5.3. I turn the switch and nothing. The security light comes on and goes off like normal. Everything basically acts as should be except no reaction from the starter. I have checked the starter and power from the purple wire to the solenoid and I got nothing. Any help would be greatly appreciated.
Submitted: 1 year ago.
Category: GM
Expert:  Shawn replied 1 year ago.
Hi my name is ***** ***** thank you for your question
Expert:  Shawn replied 1 year ago.
Have you checked the crank fuse
Customer: replied 1 year ago.
I just got the truck, the cover is missing. Which one is it?
Customer: replied 1 year ago.
I have the one in the cab. I'm missing the cover in the engine compartment
Expert:  Shawn replied 1 year ago.
Give me a min I will find that info for you. is there an owners manual with the truck?
Expert:  Shawn replied 1 year ago.
Also have you tried moving the shift lever around, or tried starting it in neutral?
Customer: replied 1 year ago.
No, lucky me. All that is gone
Customer: replied 1 year ago.
I have, still nothing.
Expert:  Shawn replied 1 year ago.
Are you able to see that photo?
Customer: replied 1 year ago.
I got it. The fuse is good.
Expert:  Shawn replied 1 year ago.
Also check any ign fuses...I assume you have a test light, check to make sure you have power on them. Also check under the dash for any aftermarket devices...remote starters, etc
Customer: replied 1 year ago.
I already have. Nothing on that.
Expert:  Shawn replied 1 year ago.
try swapping start relay with another relay
Expert:  Shawn replied 1 year ago.
Do you have a jumper wire?...by jumping terminal 30 and 87 on the start relay if your starter and wiring to starter are ok it will crank
Customer: replied 1 year ago.
Still nothing.
Customer: replied 1 year ago.
I have power to all my fuses and all are good.
Expert:  Shawn replied 1 year ago.
You jumped those terminals on the start relay and it doesn't crank?
Expert:  Shawn replied 1 year ago.
Do you have power to the number 30 terminal on the start relay?
Customer: replied 1 year ago.
Sorry, got ahead of you. No I haven't jumped it there. I have jumped it where the wire comes up the drivers side of the engine and it turned over.
Customer: replied 1 year ago.
I'll get back to you tomorrow.
Expert:  Shawn replied 1 year ago.

Ok, sounds good

Expert:  Shawn replied 1 year ago.
Let me know when your ready to proceed I have a few more things for you to check
Customer: replied 1 year ago.
What is your next idea on the Chevy
Expert:  Shawn replied 1 year ago.

Ok....disregard first photo I sent you...I believe it is incorrect. Your crank fuse is going to be in the dash fuse block....do you have the label for that. You will need to check for power there while turning the ignition to the crank position

Customer: replied 1 year ago.
I have the one for inside. I will check it as soon as I get in from work.
Customer: replied 1 year ago.
I checked it and there is no crank fuse instide. I had a friend at the parts store pull a diagram and it was the same as yours. I checked power before during and after cranking the truck. No power before or after just while cranking. I'm going to assume the first one was right. I am getting power to the fuse during cranking but no reaction. Also I'm not getting anything on the signal wire to the starter at any time. I jumped power directly to the signal wire and got the solenoid to clicking a little. So I guess the starter is shot. Can you explain how I'm not getting anything on it from the switch.
Expert:  Shawn replied 1 year ago.

Are you having someone turn the ignition to crank while you are testing for power at the starter. And that is correct that you are only getting power at the crank fuse when ignition is in crank position. If you are not getting power in crank position at the starter we need to test your starter reala circuits.

Customer: replied 1 year ago.
I'm having someone turn the switch to crank position to test it. That is the only time I get power.
Expert:  Shawn replied 1 year ago.

If you remove your starter ,relay there are four pins. Test that you have battery voltage at one of the pins

Customer: replied 1 year ago.
I do have it at two. The two closest to the cab. The other two closest to the radiator have nothing. I jumped the two like you said before and got nothing.
Expert:  Shawn replied 1 year ago.

That will be pin 30 of your relay

If you have power there...you will need to check that one of the pins has power with ignition in the crank position ( that will be power from your crank fuse). Then kitty corner to that will be ground...then kitty corner to pin 30 will be the wire that goes to your starter(pin 87 on your relay)

Expert:  Shawn replied 1 year ago.

You have constant power on two of the pins?

Customer: replied 1 year ago.
I thought that was wrong.
Expert:  Shawn replied 1 year ago.

Do you know what pin numbers they are in relation to the relay?

Customer: replied 1 year ago.
I will go check it in just a few
Expert:  Shawn replied 1 year ago.

And your fuse box looks like the first picture I sent ...everything lines up with the picture? Cause for some reason I have two different ones...I'm thinking there is a year split

Expert:  Shawn replied 1 year ago.

Wow! I'm losing my mind....I was talking with a guy with a 2000 chevy and got my self mixed up

Customer: replied 1 year ago.
That's okay. I'm going to check
Expert:  Shawn replied 1 year ago.

Okay....right diagram now....you should have power on two of them. Pin 30 is constant power. Pin 85 will be constant power in park and neutral only.

Expert:  Shawn replied 1 year ago.

Still..if you jump 30 and 87 of relay....if starter is good it should crank

Customer: replied 1 year ago.
I have already figured out that the starter is bad. The bendix engage but the rotor doesn't turn. It's locked tight.
Expert:  Shawn replied 1 year ago.

Great....that will do it then. So you are getting power at purple wire when you crank then?

Customer: replied 1 year ago.
No. No power at the signal wire when cranking. No change in the starter relay while cranking either. I'm guessing that is associated with the problem with the signal wire too?
Expert:  Shawn replied 1 year ago.

If not getting power there and relay not clicking yes there is a problem

Customer: replied 1 year ago.
What direction should I take now?
Expert:  Shawn replied 1 year ago.

So...just to recap....you do have power at 30 and 85 of relay, correct?

Customer: replied 1 year ago.
Expert:  Shawn replied 1 year ago.

OK...now what we need to check is pin 86 ...that needs to be ground when cranking

Customer: replied 1 year ago.
Ok
Expert:  Shawn replied 1 year ago.

Where are you located....is rust an issue where you are?

Expert:  Shawn replied 1 year ago.

I'm going to guess you have no ground there when cranking. Here's how this system works. When cranking ignition sends power to PCM through the crank fuse, the PCM then sends a ground signal to the start relay.

Expert:  Shawn replied 1 year ago.

Is the battery fully charged?, are battery cables clean and tight? Especially the ground at the battery and where it attaches to engine.

Expert:  Shawn replied 1 year ago.

If you have a set of jumper cables attach one end to ground on the battery and other end directly to the engine see if anything changes...I'm thinking your starter may actually be good

Customer: replied 1 year ago.
Ok. I found a jumper wire from the pcmB fuse to the pcm1 fuse. I had power on both 30 and 87 of the starter relay then. Now with out the jumper I have power on 30 with the switch on but not cranking
Customer: replied 1 year ago.
all fuses are still good
Customer: replied 1 year ago.
I don't have power to the pcm 1 fuse, the etc/exam or the ones marked 1,2 with a * by then
Expert:  Shawn replied 1 year ago.
No power to them with key on?
Customer: replied 1 year ago.
Nothing
Expert:  Shawn replied 1 year ago.
You definitely need power there, I'm sorry I am out of the shop and have no access to a wiring diagram at the moment I will have to get back to you
Customer: replied 1 year ago.
Ok
Expert:  Shawn replied 1 year ago.

OK power for those fuses come from the ignition 1 relay (the relay labeled 5 in our fuse block diagram). Check that you have constant power on pin 30 of that relay. Then chek pin 85 and 86. One should be ground and the other will be power with key in run position and cranking position

Customer: replied 1 year ago.
Between 85 and 86 which should be ground and which one is power? Or does it matter.
Expert:  Shawn replied 1 year ago.

I'm not sure which is which, it does not specify in the wiring diagram. As long as you have power on one and ground on the other, your good

Customer: replied 1 year ago.
I checked it like you said and here is what I got. That relay was missing. I have a constant power but I don't have a ground. When I established a ground with a jumper wire it tripped the relay and constantly fed power to the signal wire.
Expert:  Shawn replied 1 year ago.

OK....why missing? Alright so when you got that working with your ground....I assume everything started working and you will have power at your purple at the he started now ...i hope. Anyhow. You will need a relay for there. But that ground needs to be repaired. The ground for that comes from the left rear of the engine....bolted to thebackof the head or block. Thats where I would start :)

Customer: replied 1 year ago.
It sends a constant signal to the starter
Expert:  Shawn replied 1 year ago.
with all relays installed it sends constant power to purple on stater?
Customer: replied 1 year ago.
Expert:  Shawn replied 1 year ago.
Did you find the problem with the ground to the ign relay?
Expert:  Shawn replied 1 year ago.
Do you have something jumped somewhere?
Customer: replied 1 year ago.
Not yet. I'm not there at the moment. Ill be back in about 30 minutes
Customer: replied 1 year ago.
No
Expert:  Shawn replied 1 year ago.
Ok...let me know. How did we end up with constant power at the purple wire when we had nothing there yesterday?
Customer: replied 1 year ago.
It happens when the starter relay is in.
Customer: replied 1 year ago.
If it's not in then nothing
Expert:  Shawn replied 1 year ago.
When the starter relay is in and you have the ign relay jumped correct?
Expert:  Shawn replied 1 year ago.
this thing was starting fine before??
Expert:  Shawn replied 1 year ago.
Or did you buy this not running?
Customer: replied 1 year ago.
It does it without it being jumped. Yes. I bought it that way. I'm going to get my power probe and double check established grounds for those relays
Expert:  Shawn replied 1 year ago.
Haha...ah ok ...this is all making more sense now😂
Expert:  Shawn replied 1 year ago.
Ok ...your going to find with your ignition relay working that you have a constant ground on your start relay pin 86. At that point...verify that you do not have power at the crank fuse with the key off or in run
Customer: replied 1 year ago.
I do have a constant ground on pin 86. The only time I have power to the crank fuse is when the switch is in the crank position. So everything there is right. I'm not getting anything to the signal wire at any time now.
Expert:  Shawn replied 1 year ago.
Nothing at the signal wire..you are referring to the purple on the starter?
Expert:  Shawn replied 1 year ago.
Nothing on that because you have the starter relay out? If you put the relay in, it sends constant power to the purple, correct?
Customer: replied 1 year ago.
Not now. With all the relays in everything is right except no power on the signal wire when trying to crank it. So we have fixed part of it. What is the connection between the two?
Expert:  Shawn replied 1 year ago.

Do you still have power on 85 and 30 of the starter relay?

Customer: replied 1 year ago.
Expert:  Shawn replied 1 year ago.

86 is ground from the PCM....should only be ground there when cranking. And should have power on 85 and 30 of the start relay. 30 constant and 85 at least when in crank position

Expert:  Shawn replied 1 year ago.

So with ground on 86 and power on 85 that has to activate your relay. Or the relay is bad

Customer: replied 1 year ago.
Both 30and 85 are constant in run psi
Expert:  Shawn replied 1 year ago.

Or. Your purple wire is broke somewhere.

Expert:  Shawn replied 1 year ago.

What are you using to test powers and grounds with?

Expert:  Shawn replied 1 year ago.

You mentioned a powerprobe earlier.....do you have anything with a bulb in it...something that is going to draw some current

Customer: replied 1 year ago.
I swapped the relay with the fuel pump relay and it checked out. Fuel pump still running. If I jump power to the purple wire I get a reaction from the starter. If I jump the pins on the starter relay it arks but no reaction from the starter. What would the connection be bt the relay and the purple wire be at the fuse box? How could I test it there to maybe narrow it down.
Customer: replied 1 year ago.
I have a basic test light.
Expert:  Shawn replied 1 year ago.

Which pins are you jumping on the relay?

Customer: replied 1 year ago.
30 and 85
Expert:  Shawn replied 1 year ago.

Thats bad....don't do that. 30 and 87....87 is the purple wire

Expert:  Shawn replied 1 year ago.

87 =purple wire

30= constant power

85=power

86= should be ground only when cranking comes from PCM

Check 86 with a standard bulb type test lamp and see if it lights

Customer: replied 1 year ago.
Ok. Got it
Customer: replied 1 year ago.
86 does not ground during cranking
Customer: replied 1 year ago.
is the computer all that controls the break in the ground for 86?
Expert:  Shawn replied 1 year ago.
Ok, so your power probe was giving you a false ground signal? And yes the computer sends the ground. Have you had a scan tool on this and checked for any codes?
Expert:  Shawn replied 1 year ago.
Have you found and repaired the ground problem to the ignition relay yet?
Customer: replied 1 year ago.
It has thrown a code but I haven't scanned it yet. The ground issue isn't between the relay and the pcm. Another note, everything for my left door has quit.
Expert:  Shawn replied 1 year ago.
Right...but in order for the pcm to work properly it needs to have all its powers and grounds which may be related to not having that ground for your ignition relay
Customer: replied 1 year ago.
how do I go about establishing a ground for that? Sounds like that would be pushing in the right direction.
Expert:  Shawn replied 1 year ago.

OK there are two grounds you need to check....one is for the ignition relay the other is a main ground source for the PCM. Both are on the top back of the engine. One should be will be bolted to the block on the rear of the engine just below the head on driver side. The other should be from top down rear center of the block little towards the passenger side.

Customer: replied 1 year ago.
I found them and checked both at the engine. When I get back from work I am going to check from the other ends
Expert:  Shawn replied 1 year ago.

Ok, let me know how you make out

Expert:  Shawn replied 1 year ago.
Any luck on this beast?
Customer: replied 1 year ago.
Actually yes. I put a solenoid on today. With that and jumping power to the signal wire it finally ran. Actually running pretty good. I believe I found the short in the ground for the relay. It got dark on me before I got to try everything again but it is looking like a chewed up spot right next to the pcm.
Customer: replied 1 year ago.
Is there a fuse for all the rear lights? I don't have anything past the cab.
Expert:  Shawn replied 1 year ago.
No there is no single fuse for all tail lights. Seems this truck is a wiring nightmare
Customer: replied 1 year ago.
For not being hacked up it really is.
Customer: replied 1 year ago.
I'm about to the end of my rope. At least I think that and then something happens. Idk.
Expert:  Shawn replied 1 year ago.
Welcome to my world..bahaha. Let's get to the bottom of your starting issue then I can offer you additional service to resolve other electrical issues
Customer: replied 1 year ago.
Sounds good
Customer: replied 1 year ago.
I can't seem to get a ground from the ecm. Idk if this will help but I'm going to give a list of all ailments on the whole thing. No lights anywhere on the bed. The battery light had been on this whole time until tonight. I haven't changed anything either. I have it to a point of cranking and running pretty good except for having to jump the signal wire to excite the solenoid. I have a short for the left door. I believe it may be ground related because I can roll down the right window or lock the right door from drivers side. All the lights on drivers side door constantly flicker and nothing works on that door. The radio seems to be skipping in and out with the lights flicker. I'm at a loss. On the fuse panel in the cab, is there a relay supposed to be in there? I've got the diagram but I really don't think it's right. Not to mention there's an empty socket that is identical to the ones under the hood.
Expert:  Shawn replied 1 year ago.
What did you find wrong with the ground to the ignition relay or are you still jumping that also?
Customer: replied 1 year ago.
Jumping it. I can't find a short in it. I'm lost now.
Expert:  Shawn replied 1 year ago.
Those grounds are both good at the back of the engine? Tested with a test light...do they look rusty at all?
Expert:  Shawn replied 1 year ago.
If they are ok there. The next thing you need to do is take apart the fuse box and check the other end of the wire. I will get you exact locations tomorrow
Customer: replied 1 year ago.
Will do, thanks
Expert:  Shawn replied 1 year ago.
https://flic.kr/p/Lkov6f
Expert:  Shawn replied 1 year ago.

Hopefully this works....been trying to send this photo all day :\

Expert:  Shawn replied 1 year ago.
How you making out?