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Gm Tech (Cam)
Gm Tech (Cam), GMC Mechanic
Category: GMC
Satisfied Customers: 1685
Experience:  GM Grand Master Technician 2007. 14 year experience.
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I have a 2003 GMC Yukon XL 1500. The cluster is completely

Customer Question

I have a 2003 GMC Yukon XL 1500. The cluster is completely dead no lights nothing. Sometimes when I start the car oil gauge needle will move/ left blinker illuminates briefly but that's it. I don't think the cluster is the problem. I tested power to the connector. Ground tested good with multimeter. Has power to the 4 wires that are supposed to have power. Replaced ignition switch didn't solve problem.Symptoms are:
Dead cluster
4wd selector lights will intermittently all light up and shut off while driving, same with lights on window control switches and occasionally radio and climate control will shut off. Another weird symptom is when cluster is plugged in I cannot read any obd2 data, with it disconnected I can read obd2 data no problem.Cluster ground to any other ground has high resistance about 1000 ohms(from what I remember), same with Obd2 ground
Submitted: 9 months ago.
Category: GMC
Customer: replied 9 months ago.
Also there is a 2amp parasitic draw on the radio circuit fuse
Expert:  david craig replied 9 months ago.

Hi Im David, thanks for visiting the site. sounds to me like the BCM died.

Expert:  david craig replied 9 months ago.

what engine?

Customer: replied 9 months ago.
5.3L vorteh
Customer: replied 9 months ago.
It's the SLT model
Expert:  david craig replied 9 months ago.

ok.

Customer: replied 9 months ago.
May I ask why you asked what engine? And is there any way to test the BCM
Expert:  david craig replied 9 months ago.

because it was available with a larger engine. the only way to test the bcm is with a tech2 scan tool from the dealer.

Body Control Module: Description and Operation
BCM Controlled/Aided Functions

The BCM controls/aids the following functions. For additional circuit information and descriptions, refer to the appropriate sub-system.

RKE Remote Keyless Entry/Panic Alarm/LOCKING and UNLOCKING of Doors/Lockout Prevention

DRL Daytime Running Lamps/Auto Headlamps/Exterior Lighting

VTD Vehicle Theft Deterrent/Passlock(TM) System

Inadvertent Power Relay/Battery Rundown Protection

RAP Retained Accessory Power

Interior Lighting

Audible Warnings

The BCM performs the BCM functions in the wake-up state. The BCM enters the sleep state when the active control or monitoring of system
malfunctions has stopped, or when the BCM is idling. The BCM must detect certain wake-up inputs before entering the wake-up state. The BCM
monitors the BCM inputs during the sleep state, allowing the BCM to switch between the 2 states. The BCM wake-ups are as follows:

Door ajar switches

Door handle switches

Dome lamp

Park lamps

Power door lock switches

Interior lamp request active

Ignition key put into the ignition switch

Ignition key removed from the ignition switch

Ignition in the RUN position

Key in door lock switch

RFA request to the BCM

Any Class 2 communication requiring BCM interaction

Customer: replied 9 months ago.
I have a snap on modis. Would this be able to test the bcm?
Customer: replied 9 months ago.
Also last question, where is the bcm located?
Expert:  david craig replied 9 months ago.

Body Control Module: Reading and Clearing Diagnostic Trouble Codes

With Diagnostic Scan Tool

PROCEDURE

A Tech II or equivalent Scan tool must be used to retrieve Diagnostic Trouble Codes (DTCs) from the PCM memory. DTCs can no longer be
retrieved at the data link connector. This also eliminates the PCM function of flashing Code 12. Follow the instructions supplied by the Scan tool
manufacturer in order to access and read either current and/or history DTCs.

With Diagnostic Scan Tool

PROCEDURE

Use a Tech II or equivalent Scan tool to clear Diagnostic Trouble Codes (DTCs) from the PCM memory. When clearing DTCs, follow the
instructions supplied by the Scan tool manufacturer.

NOTES:
Do not clear the DTCs unless directed to do so by the service information provided for each diagnostic procedure. All of the diagnostic data

that was saved along with the DTC (freeze frame data and/or malfunction history records) which may be helpful for some diagnostic
procedures will be erased from the memory when the DTCs are cleared.

Interrupting PCM battery voltage to clear DTCs is NOT recommended

CIRCUIT DESCRIPTION

Normal vehicle class 2 communications and module operations will not begin until the system power mode has been identified. Discrete wires from
the ignition switch contacts are monitored by the power mode master (PMM) module in order to determine the correct power mode. The PMM
communicates the system power mode to all class 2 modules on the class 2 serial data line. Refer to Body Control System Description and Operation
to identify which module is the PMM and the applicable power mode look up table

Expert:  david craig replied 9 months ago.

you can try it with the modis, ive never had to. always used a tech2

Expert:  david craig replied 9 months ago.

any luck?

Customer: replied 9 months ago.
New bcm. Still cluster still dead
Expert:  david craig replied 9 months ago.

did you test it with the modis?

Customer: replied 9 months ago.
Not yet about to momentarily.
Expert:  david craig replied 9 months ago.

ok. keep me posted.

Customer: replied 9 months ago.
About to test with modis now. Had to find the power cord. Also another weird symptom: when I put into park door locks will actuate 4-5 times.
Customer: replied 9 months ago.
Basic trouble codes
Customer: replied 9 months ago.
Continued
Customer: replied 9 months ago.
Going into body control module tests now. Scanner can't communicate with it to read codes
Expert:  david craig replied 9 months ago.

BCM has got to be wiggin out

Customer: replied 9 months ago.
I'm doing a power down test right now
Expert:  david craig replied 9 months ago.

ok

Customer: replied 9 months ago.
Codes on the bcm. After about 10 seconds scanner says an error occurred and I have to cycle the key for power to get any info from bcm. What do you think the possibility it is a short somewhere? The bcm I got was a used one and had a different part number then the old one but it matched the part number the dealer gave me for the VIN
Customer: replied 9 months ago.
This issue is starting to get the best of me. :Sigh:
Expert:  david craig replied 9 months ago.

im out of ideas my friend. im going to opt out and let another tech chime in. this is way to deep

Expert:  Jake Cheek replied 9 months ago.

Hi my name is***** me take a crack at this. To recap, new BCM, codes stored.

1. Are there "No communication" codes stored and what are they?

2. You stated "Cluster ground to any other ground has high resistance about 1000 ohms(from what I remember), same with Obd2 ground" Can you double check that for me? Are you testing it at the cluster and with it unplugged?

Just from reading this I believe you have a ground short on a communication or module circuit. If you have poor ground to the cluster I would run a new ground wire and see what that does. It does not have to be pretty, this is for testing purposes only.

Expert:  Jake Cheek replied 9 months ago.

I also found a known harness pinch point under the drivers seat that can cause some if not all of your issues. Here is the description and a diagram of where to look.

A chafed or pinched seat wiring harness under the driver seat may be a cause of this condition. Because of the routing, a portion of the seat wiring harness may rest on the inboard edge of the seat track or frame. Over time, the harness may be pinched or chafed because of the seat movement. Refer to the above illustration. The illustration shows the inverted position of the seat bottom. The arrow shows the primary location of the possible harness chafing/pinching.

Customer: replied 9 months ago.
I don't see any obvious chaffing or any pinched spots but maybe I'm missing something you can see?
Customer: replied 9 months ago.
Second photo
Customer: replied 9 months ago.
Let me test resistance again as my cousin did it the first time. I believe it was resistance between good ground and ground going directly to cluster connector
Customer: replied 9 months ago.
48 ohms of resistance from good ground to obd2 connector ground. And 48 ohms from good ground to cluster connector ground
Customer: replied 9 months ago.
I ran a new ground wire already actually, directly to cluster ground before the connector, didn't make a difference. That was with the old bcm though. I wired everything up back normally when I installed new bcm so I can try it again
Customer: replied 9 months ago.
With good ground spliced into back of cluster connector (solid black wire) resistance is respectively 0. Interestingly now solid Black ground to obd2 connector is 8 ohms of resistance with car off, with car on jumps to 80 ohms. Going to splice good ground into obd2 connector now
Customer: replied 9 months ago.
Can you see the conversation from before with the last tech? I sent pics of the modis screen with all the codes
Expert:  Jake Cheek replied 9 months ago.

I can see I was just making sure nothing new came up or codes had cleared. You should not have any resistance to ground from the DLC or cluster. With the key on and higher resistance makes me think a module is grounding something it should not be. I would start by unplugging modules and checking the ground at the DLC. Start with the ECM.

Customer: replied 9 months ago.
Where is the ecm?
Expert:  Jake Cheek replied 9 months ago.

It is on the drivers side under the hood. here is a diagram. Make sure the key is off when you disconnect it.

Customer: replied 9 months ago.
Well I found a 2amp draw on the radio circuit. Should I pull the radio and look for bad wiring?
Customer: replied 9 months ago.
Or do you think this has something to do with the actual radio unit internally!
Customer: replied 9 months ago.
internally?
Customer: replied 9 months ago.
Any chance this could be the problem? Lol
Customer: replied 9 months ago.
I have no idea what I'm looking at here. Seems to be some type of interference shielding for the speaker wiring. Is this factory? How would I even repair correctly?
Expert:  Jake Cheek replied 9 months ago.

It could be that the radio has a draw, but there are a few circumstances where it is made to do that. I do think 2amps is a bit high, but it really doesn't fit your symptoms. I took a look at this pictures you sent and it may be factory wiring that had the loom tape pulled off. As long as there are no bare wires or chaffing it looks okay to me.

After quite a bit of digging I found all of your no communication codes are related to a splice pack - SP205 - its where all the communication goes from each module to one location and they can cross talk. So either the splice pack is bad, maybe corrosion, one of the data lines is shorted, or one of the modules on the data line is bringing all the other modules down. There is one sure fire way to test this.

1. Reconnect all modules.

2. Disconnect the splice pack. It is like plug to a connector, black in color, 12 pins, with wires only coming out of one end and a "cover" which is just a pinned piece of metal connecting all of the pins together - it must be disconnected and inspected. If you don't find an issue, continue to the next step.

3. Then you must jump all of the pins to each other. 12 total. I do this by taking 12 wires and crimping terminals to them and connecting the other ends together to make a spider looking jump wire. How you do it is up to you as I doubt you have access to terminal pins. You could use paper clips? As long as they are all in the connector pins and touching you can remove one by one.

4. Then one by one unplug and check if you have communication to the rest of the modules with the scan tool. If you still don't, plug that one back in and go to the next.

The point is to get all of the modules connected together and unplug the bad module or circuit. This splice pack is being the left instrument panel fuse block. I will attach a diagram.

Customer: replied 9 months ago.
Is that it? Thank you for you research and help this is definitely one of the most in depth electrical issues I have ever delt with
Customer: replied 9 months ago.
To the left with the gm 4135 is the back of the fuse panel (for reference)
Expert:  Jake Cheek replied 9 months ago.

That looks to be it! Awesome, I am glad you found it. It looks like a pain to get too lol.

Customer: replied 9 months ago.
Man, pictures do not do it justice. Currently devising a plan lol
Expert:  Jake Cheek replied 9 months ago.

Alright I'll be here.

Customer: replied 9 months ago.
I don't see any issues with the spice pack, looks good. I'll grab some paper clips and the scanner and see what I come up with
Customer: replied 9 months ago.
Wouldn't jumping these pins like this only connect one pin to another pin when the splice pack connects them all to each other?
Customer: replied 9 months ago.
On an unrelated note, I'm not sure if this is normal near the driver side fuse panel seems to be an open port. Not sure if it's for diagnostic or what but is there supposed to be something there?Secondly this was equipped with what I'm assuming is factory head rest Tvs. Just though I would note that in case you have any insight on that
Expert:  Jake Cheek replied 9 months ago.

Yes, you are close though. So each pin would need its own clip and then all the ends of the clip should touch. That's a lot of paper clips! Usually the way to do this is with wires. I guess you could stick wires in from the back where the wires go into the splice pack? May be easier than holding paper clips and checking communication? I'm sorry if I'm not explaining this right.

Customer: replied 9 months ago.
Driver side panel open connector
Customer: replied 9 months ago.
Headrest tvs
Customer: replied 9 months ago.
No worries I'll get it done somehow. Probably a good idea to go run out and get a basic wiring kit
Expert:  Jake Cheek replied 9 months ago.

I don't think this will effect the issue you are having. Those are not on this data circuit.

Expert:  Jake Cheek replied 9 months ago.

Could you send me a picture of the splice pack insert? Not that I don't trust you, I would just like to see the configuration.

Customer: replied 9 months ago.
No worries here it is
Customer: replied 9 months ago.
Here's another one
Expert:  Jake Cheek replied 9 months ago.

Alright thanks. I thought maybe there would be a way to use it for testing but I think a wiring kit of some sort is your best bet.

Customer: replied 9 months ago.
Going to clear the codes and scan one more time before running to the store to get the kit. I'll post the results here in a sec
Customer: replied 9 months ago.
Same.
Customer: replied 9 months ago.
Here's the codes stored in the history
Customer: replied 9 months ago.
Customer: replied 9 months ago.
the power train trouble codes
Customer: replied 9 months ago.
Probably redundant info just though I'd provide it. Going to run to the store now. Thanks
Expert:  Jake Cheek replied 9 months ago.

No you're right, its a good idea to have a base to go off of once you start pulling data lines. I'll be here

Customer: replied 9 months ago.
Now the car won't stay running. Engine will turn. Start then immediately die
Customer: replied 9 months ago.
It honestly might be because of gas though. I'll grab a couple gallons when I'm out. First I'll try disconnecting the battery for a second and try again. Maybe bcm just trippin
Expert:  Jake Cheek replied 9 months ago.

If the splice pack connector is out it probably won't run.

Customer: replied 9 months ago.
I put it back in. Not completely snug though, since it's a bitch to get out
Customer: replied 9 months ago.
Pretty sure it's out of gas. Hopefully.
Customer: replied 9 months ago.
I noticed the ground from the body to the hood is not looking to great. Not sure if that is related
Customer: replied 9 months ago.
I still need to unplug the ecm and check resistance at the dlc. Let me do that real fast
Customer: replied 9 months ago.
At dcm with ecm connect. Solid black 0 ohms. Black with white tracer 60 ohms (ground tone comes on though)
With ecm unplugged. Solid black 0. Black with white tracer 66 ohms
Expert:  Jake Cheek replied 9 months ago.

From what I can tell the black/white wire should be a solid ground through the relay block behind the instrument panel. I don't think there should be resistance on that wire to ground. Its ground 203 under the dash - looks like around the area of the splice pack? I'm sorry its a terrible picture really.

I do think we should check the modules first though. I really think we have a communication issue with one of the data lines or modules. If that doesn't pan out we can start looking for loose grounds or something shorted. Easiest to hardest.

Customer: replied 9 months ago.
I'm going to fab something tonight and test the modules in the morning. So in short basically see if the modis can connect to each module and disconnect one by one? Which modules should I be keeping an eye on? Yeah that ground looks like a nightmare to get to definitely will check the modules first
Customer: replied 9 months ago.
Any way this could be a relay issue?
Expert:  Jake Cheek replied 9 months ago.

Anything is possible but that is not one I have come across, especially causing a communication code, let alone multiple. Once we are sure the data lines and modules are okay I will dig deeper into other possibilities. Don't worry I think we are getting closer.

Customer: replied 9 months ago.
Man, I honestly don't know if what your thinking is honestly possible. I tried wiring up a contraption it wouldn't stay in. The next idea would be to solder some wire to the end of paper clips and try it that way. Before I do this is this honestly the next logical step because it's a real pain
Customer: replied 9 months ago.
Also what module is this?
Expert:  Jake Cheek replied 9 months ago.

Well the only other way would be to release the terminals from the connector and plug the splice pack back in. It may take longer but it may be easier. For each terminal there is a little black clip holding it it. Push it up and pull the wire out from the back. Now plug the splice pack back in. You will have to repeat these steps for each circuit.

Expert:  Jake Cheek replied 9 months ago.

If you can get me the part number I should be able to look up the module.

Customer: replied 9 months ago.
12580061
Expert:  Jake Cheek replied 9 months ago.

Transfer case shift control module

Expert:  Jake Cheek replied 9 months ago.

I believe that is one of the data circuits we are testing. Did you find something?

Customer: replied 9 months ago.
No I was just wondering what it was. I saw a large ground wire running to it that's why I ask. I'm going to try to remove the pins
Expert:  Jake Cheek replied 9 months ago.

Ah, okay. Well let me know if you can get a pin out to test.

Customer: replied 9 months ago.
Ok I soldered something up
Customer: replied 9 months ago.
I noticed there's only 10 of the 12 pins on the splice pack. Don't know if that's normal or not but I have my wiring in to the 10 that are there
Customer: replied 9 months ago.
Transfer case ok
Passenger presence system ok, has class 2 data link codes
Ipc not plugged in so no communication(not sure whether to plug in or not
Hvac ok but has class 2 data link codes
Passenger door module ok no codes
Driver door module ok no codes
Bcm ok same codes
Airbag ok codes b1001, u1000
Abs has no codes, history code for c0291 lost data from bcm
Power train ok has lots of codes
Customer: replied 9 months ago.
Not sure what to do next or what to disconnect
Customer: replied 9 months ago.
Cleared codes on all modules. Interestingly when I hit clear on the passenger presence system all the lights on the radio hvac doors and 4wd flicker on and off 3-4 times. When I plug in the cluster there is no communication with passenger presence system. I will check all modules now with cluster plugged in
Customer: replied 9 months ago.
Keep in mind this is with a manual ground connection to the cluster it's self
Customer: replied 9 months ago.
I think I may have been splicing the wrong ground to the cluster. I regrounded the solid black wire. I'm assuming it is black with white tracer
Customer: replied 9 months ago.
No continuity tone or resistance on pin a3 at the cluster black with white tracer
Customer: replied 9 months ago.
Ok nvm I'm right http://nebula.wsimg.com/4096bf1e901b887bddb1ed95edd037d3?AccessKeyId=C551C8582E964E563B91&disposition=0&alloworigin=1Pins A12 and b12 on the ipc are the grounds
Customer: replied 9 months ago.
A12 has 112ohms of resistance. B12 has around 50ohms
Customer: replied 9 months ago.
Both chime on the ground test
Customer: replied 9 months ago.
With the cluster plugged in even with both a12 and b12 to good ground. Almost none of the modules work with exception to the door lock modules. Not sure what to do next in terms of what to disconnect from the custom splice pack maybe you can guide me here and let me know what to look for
Expert:  Jake Cheek replied 9 months ago.

So with the cluster unplugged do you still have high resistance in the ground circuits? It may be the cluster is bad and grounding out.

Customer: replied 9 months ago.
high resistance with unplugged
Customer: replied 9 months ago.
I honestly don't think it's the cluster, I could be wrong but this is the 3rd one I have tried
Expert:  Jake Cheek replied 9 months ago.

Yeah you are probably right. If it doesn't have good ground without it plugged in that would not be a bad cluster. Let me look up a diagram real quick.

Expert:  Jake Cheek replied 9 months ago.

Okay do my a favor. With all the modules plugged in, check for ground at the splice pack. Then check for power as well.

Customer: replied 9 months ago.
You meet with the splice pack plugged in check for ground behind the connector? Or with the splice pack completely out check for ground?
Expert:  Jake Cheek replied 9 months ago.

Plug the splice pack back in and check for ground and power at any of the wires plugged into the back of the splice pack

Expert:  Jake Cheek replied 9 months ago.

Maybe we have a module feeding back ground or power through the communication line. If you find either, unplug the splice pack and check each individual wire and let me know what pin it is.

Customer: replied 9 months ago.
They all have power none of them have ground
Customer: replied 9 months ago.
Really low power, like .3 volts. Battery was getting low though so I can let it run for a while the check power again
Expert:  Jake Cheek replied 9 months ago.

Oh okay, really low voltage is normal for a data line. So I think we've eliminated data lines. It is not the cluster and has a new BCM. Did you have the BCM programmed when you replaced it?

Expert:  Jake Cheek replied 9 months ago.

I keep coming back to the drivers seat harness. Seeing now that you have Passenger Presence Module with communication codes as well. I missed that earlier. I think it would be a good idea to go through and check the large harness under the seat just to make sure we aren't chasing something that isn't there.

Customer: replied 9 months ago.
I didn't have the bcm programmed but I really want to leave that as the last resort because the dealer wants an arm and a leg to do it. I'm assuming it should atleast give power to the cluster if it was. I'll rip both the seats out tomorrow and go through the wiring. The diagram you showed me of the pinched/chaffed wiring more so reflected the passenger seat more than the driver but either way I'll check them both out
Expert:  Jake Cheek replied 9 months ago.

Okay sorry I should have clarified drivers side!

Expert:  Jake Cheek replied 9 months ago.

I don't think you have to take the passenger side out. There is a known pinch point under the drivers seat.

Customer: replied 9 months ago.
No, you did specify drivers side but the diagram looks more like the passenger for some reason. I'll give it a go tomorrow. My gut tells me there's got a be a short somewhere, but I'm no expert lol
Customer: replied 9 months ago.
Hopefully it's under the seat, I'm hoping
Customer: replied 9 months ago.
If it is the wiring under the seat wouldn't disconnecting the seat solve the problem?
Customer: replied 9 months ago.
I have the seat out, looking at the wiring, also noticed there is a module underneath the seat that connects to the seat
Expert:  Jake Cheek replied 9 months ago.

Yes that is the Airbag module, do not remove it.

It could prevent the issue but most likely not when unplugged. I would remove the plastic loom at bends and pinch points to see if it is damaged.

Customer: replied 8 months ago.
Sorry for the late reply I'm going to check out it out now
Expert:  Jake Cheek replied 8 months ago.

Okay sounds good.

Customer: replied 8 months ago.
Still looking through this seat wiring but I did test resistance to both dcm and ipc with the seat disconnected and still read high
Expert:  Jake Cheek replied 8 months ago.

Yeah that could be that two wires are touching or broken in the harness further up. Keep me posted.

Customer: replied 8 months ago.
further up the harness in the vehicle not the seat correct?
Expert:  Jake Cheek replied 8 months ago.

As far as I can tell there have been problems with the harness that is under the seat. That and the image of the harness is really the only information I have found. Did you remove some of the harness cover to physically check the wires for chaffing?