[84 400]

not sure on he temp gauge but i do have a good hint to the auto lights. on my dads tahoe they developed a mind of there own as well as the hih beams. first it was a chaffed wire that cause one to be out ( unrelated to this problem). after dumping alot of time and money into those lights we found out it was acctually the high beam switch causeing the problem. not the headlight switch as orginal thought( my uincal works at the gm plant in michigan and got a switch but it made it no diffrent) So after payin a specialty shop to look at the elctronics after the dealer could not fix it it was the highbeam/turnsignal lever. hope sthis helps this was on a 2000 tahoe