GEM is the module that controlls alot of the electrical relays and controlls in the cab..... IE Door locks, windows, wipers, and interior lights and such....

 

and it sits on the tunnel right under that dash?

 

It's bolted to the back of the interior fuse panel located right above your left foot when you're in the driver's seat.

 

oh ok. does any one know what sits on the tunnel? mine has a black plastic cover that goes around it.

 

i know ONE of the things under that covers the turn sig relay, my uncles got an 01 tows trailers with bad light systems all the time and its gone bad 3 or 4 times so far but other than the smart relay i think theres 2 more relays, maybe 1 but i think 2...