Guys a couple of questions, A few weeks ago I have noticed that the factory Trans temp gauge ('02) started bouncing from the bottom to the middle, not always (sometimes all is fine) but it happens enough to drive me nuts and then last night after changing the batteries I noticed the tach was sticking then returning to normal operation along with the temp gauge. I have been getting weird warning lights on the dash this winter as well, what I mean is they come on indicating their function when you turn on the key but they won't go off until after the truck and cab have warmed up. (Been cold with some really big, wet snow storms this winter, so alot of moisture and condensation) Wondering if if I might have a bad relay or connections to one, any suggestions?

Thanks for the help in advance.

 

Sounds like an electrical short somewhere - Had a problem like that years ago in a chevy truck. Wound up being the hot wire from the battery was rubbing on the manifold & when the truck got hot the gauges would start jumping all over the place. Took me a couple weeks to finally find the problem. Good Luck

 

Bill, thanks, I could not find a short but that does not mean it aint there. It is only the trans temp gauge, none of the other gauges (except the tach for little while last night and it was sticking not randomly bouncing) and it only does it sometimes. I am thinking now and it could be a faulty sending unit for the trans temp gauge. I know some guys have said there is a relay that supplys power to the dash or gauges that sometimes acts up but I don't remember which one it was, that may the problem with the intermitent dummy lights that go away after it runs fow awhile, any help?

 

Just had the EXACT same problem. Water, was leaking thru the bottom seal, drivers' side, and somehow manage to drip right on the GEM module, which just so happens, controls somewhat ALL electrical functions.

However, the GEM module was installed from 99-e01, then from l01-02, i believe, they used a VSM module, i think. Not sure if its located in the same spot, but the GEM is behind the fuse panel, bolted behind it.

Do a searcg on GEM, and i think, you'll find ur problem.

 

Thanks Tim, will do a search and check out the truck.