2007 GMC Yukon Electrical Issues

[risbell]

I have a 2007 GMC Yukon and am having some weird issues with the electrical.

When I turn my blinker on the rear air turns on. Same thing happens when I turn on the radio. When I turn them off the air will go off. When its on it makes a loud whining sound and seems to get louder when I press the gas.

I also noticed my headlights will blink while I am going down the road. Not really sure what that is.

I'm not very mechanically inclined so any help would be appreciated.

Thanks

 

[petethepug]

Welcome from SoCal. A couple of Q’s for ya. Is it a Denali (6.2L) or standard (5.3L)? XL or shorty? Milage when you got and now, plus how long have you owned it? Any recent work done on it and/or is this a new issue?

On these trucks electrical is controlled through a 5V CAN/BUS diagnostic line. When the main battery cables go bad from internal corrosion after a decade (like right now) you’ll have wonky behavior occurring from low voltage & bad grounds. You’ll also have false codes appear because the 5V diagnostic line is too weak to work properly.

Bottom line. Start on solid ground. Replace both battery cables if it has not been done. THEN, see what’s really there and left over. A dealership would love to have you visit and spend 2-$3k on diagnostic time and $200 on battery cables that cost $60 from RockAuto.

 

[Joseph Garcia]

^^^^^x2^^^^^ I would first assume that your issue is electrical in nature, and as @petethepug suggested start with the battery cables, followed by the engine to firewall ground, and then the body grounds to ensure that they are in good condition, and the contact points are clean and tight.

 

[JPS0284]

Welcome from SoCal. A couple of Q’s for ya. Is it a Denali (6.2L) or standard (5.3L)? XL or shorty? Milage when you got and now, plus how long have you owned it? Any recent work done on it and/or is this a new issue?

On these trucks electrical is controlled through a 5V CAN/BUS diagnostic line. When the main battery cables go bad from internal corrosion after a decade (like right now) you’ll have wonky behavior occurring from low voltage & bad grounds. You’ll also have false codes appear because the 5V diagnostic line is too weak to work properly.

Bottom line. Start on solid ground. Replace both battery cables if it has not been done. THEN, see what’s really there and left over. A dealership would love to have you visit and spend 2-$3k on diagnostic time and $200 on battery cables that cost $60 from RockAut

This would be the perfect excuse to get away from the wife and finally buy an oscilloscope to nerd out in the garage ogling at low V square waves.