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Amedee, GMC Technician
Category: GMC
Satisfied Customers: 26055
Experience:  ASE Technician advanced level specialist
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2006 GMC Yukon: had a fire under the hood and the alternator

Customer Question

2006 GMC Yukon: had a fire under the hood and the alternator and battery were replaced. They couldn't get the truck to run, just turning over and over. Sent it to the place that installed the alarm, they disabled the alarm, and auto starter. Still no start, finally the gm dealership and they tell us the ground wire needs to be hooked up to the coil, and it was not.
We get the truck back it will run and then die, run then die. This goes on for two days and now everything is dead!
Submitted: 11 months ago.
Category: GMC
Customer: replied 11 months ago.
Need to add that although they told me the ground wire needed to be attached to the coil that is not what they did, they put it to the engine and the frame.
Customer: replied 11 months ago.
Also after driving 2 blocks yesterday and bringing it back home after 2 stalls the negative wire was hot as heck and so was the battery.
Expert:  Pete replied 11 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

I suspect you have a dead short with the battery cables with wiring shorted on the engine area.It does sound like they connected the ground properly as one should go to the back of the cylinder head and one to the frame.

Did they inspect all wiring in the engine bay area for any damaged or shorts at all?

Let me know,thanks Pete

Customer: replied 11 months ago.
I suspect there is still a short? I also don't understand why the work order says they connected the ground to the coil, when they clearly didn't ?
I can't find anything that clearly says where the ground wires should go, I also seem to have a burnt out ground wire hanging underneath close to the bumper.
Expert:  Pete replied 11 months ago.

Most likely the service writer typed in ground to coil but what was done was ground to engine block and ground to frame.Sometimes they type it up incorrectly after the repair is done.

When the battery and cables are hot like this here this indicates there is a short from ground to power leading to the battery or that there is still a poor ground issue.

Can you take a picture of this ground wire and post it here at all?

Customer: replied 11 months ago.
Yeah, it will take a little bit, just making breakfast still! Lol
Expert:  Pete replied 11 months ago.

No problem.I will be here most of the day as well as all week.Reply when your ready.

Thanks Pete

Customer: replied 11 months ago.
First photo shows the negative connector and the second shows the connector and to the left the smaller wire attached to the frame. I took the battery out because I was afraid it would start on fire in the driveway again!
Third photo is the wire that hangs from behind the front bumper and is burnt off right where you see the sun light! I am presuming this is where the negative wire previously was attached to the frame?
I can't seem to get a photo that makes sense of the large wire that goes down and attaches to the motor?
Customer: replied 11 months ago.
3rd photo
Expert:  Pete replied 11 months ago.

This is a tough one for me to answer myself here.

I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete

Customer: replied 11 months ago.
I understand, I was married to a gm mechanic for 15 years, sometimes you can't diagnose when you SEE it ! I think what disturbs me is I don't have a definate cause of the fire to begin with and it just seems whatever the cause was still exists even after the new alternator and battery.
Expert:  Amedee replied 11 months ago.

Hello and welcome! Different tech here. I would like to help you diagnose this no power problem. Are you saying that the engine cranks but does not start? Or does it not even crank over and no power to anything?

Customer: replied 11 months ago.
Customerit was towed to an auto electric shop this morning, so I shall just wait for the bill now. Thank you for responding.
Expert:  Amedee replied 11 months ago.

Your welcome!