Electrical problems
 

HELP, I own a 2002 G500 with some real problems. I purchased this Wagon on the internet(bad idea) I flew to Chicago to drive this car home and before getting home I lost my
headlights. After making it to New Mexico I lost all of the dash functions. Turn signals,Warning panel and then the Throttle position sensor(limp home)
then the transmission went into the limp home. After 16 months in a shop and several trans. computers it shifts.
Drove it home boy was I happy. And a lot poorer.
Drove it approx. 50 miles and the Head lights quite again. Turned out to be dirty connections. Then I found that every thing from the rear dome lights back no longer
worked. Rear turn signals . Side markers, Plate lights Stop lights and parking lights.
I was told that it was the rear SAM.
I purchased a Rear SAM from a dealer in Arizona and they sent me a different part number $856.00 said because of my VIN number my car used a different SAM.
They don't let you return elec. parts even when they send a completely wrong part. None of the wires will plug into this new part.
I then found a rear a SAM on ebay installed it and still nothing works and I now have dash problems and throttle position failure.
Can someone tell me it there is another box that controls the rear lights?

If I can't repair this car soon I will sell it real cheap.