Exterior signal lights all work incorrectly in my 2005 yukon. All the bulbs light up but not correctly when using break or turn signals. The turn signals all blink whenever I try to signal either direction. The hazard lights illuminate when I break. The cruise control doesn't work when headlights are on, and reverse lights don't work at all.

wyet

• 510 Answers
• Posted on Aug 10, 2011

SOURCE: brake lights don't work when

{: ) Looks like your lightings got haywired. Have you had vehicle repairs recently? Anyway, it seems that you have poor grounding connections for the affected lightings. Some circuits share common ground, and ground terminals are strategically distributed on the vehicle. If these grounds don't have good contact with the body, chassis, or engine ground, circuit functions are badly affected. Thats why these ground points should be inspected and kept clean and tight, maintain that good wire and terminal contacts.
We can start with G100 located at the Left Front of the Engine Compartment on the left front body mount. See diagram below:


Check out also G401 which is located in the chassis harness, mounted to the left rear Body mount. This ground point is shared by the rear lamps like the brakes, reverse, and rear signal lamps.
If possible check also other ground points that you may visually come across while on your search. Be sure also that fuses are all inspected good.
I hope we get lucky in finding and fixing a certain lamp function, if not all. Goodluck.