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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15201
Experience:  GM Grand Master Technician 2007. 14 years experience.
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What electrical issue does my '07 avalanche have that causes

Customer Question

what electrical issue does my '07 avalanche have that causes the coil packs to be replaced?
Submitted: 1 year ago.
Category: Chevy
Expert:  AZTechBrian replied 1 year ago.

Hello. Is it the same coil that keeps going bad? different coils? all coils? what are all the details. I'll try to help you as best I can.

Customer: replied 1 year ago.
mainly 1 and 7.
i have had replace them multiple times in the 4 years i have owned the truck
Customer: replied 1 year ago.
the time i did not replace one, it made the transmission jump going into 1st gear and ended up replacing the trans.
aprox a year ago and it is starting to jump again
Expert:  AZTechBrian replied 1 year ago.

have you also replaced the spark plugs? Bad plugs cause a coil to have to work harder and will cause premature failure. The other consideration is the quality of the coils. Are they OE coils, or are they the less expensive parts store brand coils? less expensive aftermarket coils are often just prone to failure much earlier than one would expect.

Customer: replied 1 year ago.
two years ago it had a complete tune up at the dealership. all plugs and wires were changed.
it did it then and with the aftermarket ones i have bought.
Expert:  AZTechBrian replied 1 year ago.

Ok, so it prematurely burned out the dealers OE coils when they replaced them at the same time as the plugs?

Customer: replied 1 year ago.
we have done quite a bit of work to the engine (recall things the former owner didn't do)
and still having same trouble. i'm starting to think it has something to do with the wiring harness?????
Customer: replied 1 year ago.
that is the reason i went to aftermarket
Expert:  AZTechBrian replied 1 year ago.

Sorry about the delay. Let me check into something.. one minute

Expert:  AZTechBrian replied 1 year ago.

Ok. I wanted to check for technical service bulletins. There aren't any. Have you inspected the wires for any damage or shorts to ground? Everything look good?

Expert:  AZTechBrian replied 1 year ago.

wires in the wiring harness, not spark plug wires..

Customer: replied 1 year ago.
according to the techs at the dealership everything was ok.
that's all i have to go on.
but it is obvious there is something somewhere???????
Expert:  AZTechBrian replied 1 year ago.

I would take a good look at the wires at the connectors and just look over the wires in the harness for any damaged wires. Let me know if you find anything. Usually premature coil failure is either a cheap coil, or a bad plug.. it sounds like those options have already been ruled out though.

Customer: replied 1 year ago.
thank you for your help
Expert:  AZTechBrian replied 1 year ago.

Your welcome. Let me know what you find. I am curious, do they both fail at the same time?

Customer: replied 1 year ago.
not yet.
one or the other.
and i always know when one is ready to go because my dash reads things like....check stability control, ect...
which it is doing it now
Expert:  AZTechBrian replied 1 year ago.

is it running rough yet?

Customer: replied 1 year ago.
only when you are sitting at an idle.
after that you can't tell anything is wrong.
Expert:  AZTechBrian replied 1 year ago.

have you checked to see if there are any codes yet?

Customer: replied 1 year ago.
i will stop and have it checked after work today.
Expert:  AZTechBrian replied 1 year ago.

ok.. please let me know what is stored when you find out.