Wiring problems of the 2003 GMC Yukon

Vehicle randomly goes into reduce engine power mode and stalls while driving. This has happened multiple times while driving on a highway and going up a hill where it nearly caused a three catastrophic accidents. Basic research shows that gm has known about this issue since the vehicles were a few years old and it affects many years of gm vehicles. There is a problem with bad grounding connectors related to the throttle body sensor and and wiring harness.

"reduced engine power/stalility control disengaged" message displayed, engine went to idle and would not exceed 5-10 mph. Traffic from behind served to avoid decelerating vehicle. I understand this is something that is somewhat common with these gm models. The possibility of rear end collisions may be experienced due to rapid deceleration due to loss of power. Happened intermittently again during the day. It clears itself after the vehicle sits for a while but there is no warning when it might happen again. Information received form various forums state it is believed to be within the wiring harness for the throttle position sensor.

I have had multiple ongoing electrical issues with this vehicle. Starting in 2005, the exterior electronics (I. E. Signal lights, stop lights, head lights, etc) began to malfunction. For example, I would trigger the signal for one direction and all of the signals for all directions would trigger. . . Even pressing the breaks triggered all of the exterior signals. The dealer had a hard time isolating my problem, but after several visits, the dealer was finally able to diagnose and rectify it. . . They isolated it to a junction box where all of the electronics terminate. However, by this time, my vehicle was out of warranty, so I had to cover the costs for reparing the problem myself. My most recent issues, which, by the way, seem to be common issues, are triggered by a message stating, "reduced engine power". This particular issue does not always render the same results. . . Sometimes the vehicle's speed will significatly decrease to nearly a halt, but other times I may just experience increased idling of the engine, even if I am at a complete stop. My understanding, according to hundreds of reports that I have read on the message boards, is that this issue is caused by either a wiring harness that leads from the excellerator to the throttle body or it's a defective throttle body alltogether. I have experienced intermittent electrical problems with my windows as well, but this appears to be a minor issue when compared to the other two that I addressed above. I will file a formal complaint with GMC corporate office today and see where that goes.

Headlight flicker had dealer work on it and replace one headlight but this did not correct the problem. Dealer said this was normal. Notice the flicker when I go over bumps or when cornering to the left.

After noticing that my 2003 Yukon denali had intermittent headlights/dash lights dimming, I took the vehicle to my local dealer to have it checked out. They presented me with a document that stated the gm stated this was not a malfunction and was a normal condition. There is nothing about this that is "normal". Any time, at night, a curve is taken at above 35 mph the lights flicker. I had already pinpointed that it had to do with the vses system because when the vses is turned off, this does not happen. When a curve is taken and the flickering occurs, the voltage meter for the battery drops substantially and then goes right back to normal. This is a distraction for the driver (myself), any oncoming traffic, and anyone that I am behind. This absolutely needs to be looked into before it causes injury.

When the vehicle headlamps or park lamps were turned on, the electric trailer brakes would not respond when the vehicle brakes were applied. The consumer felt that gm should cover the expenses. . The dealer stated the brake wiring harness from the previous year was not compatible with the current year model because the electrical systems were different and a new wiring harness needed to be purchased.