only on high
 

ok heres the problem i have a 96 tahoe and my a/c, heater only work on max, wipers only on high, and only my high beams i dont know what this could be maybe a relay. im kinda stumped and dont want to pay a ton in labor

RE: only on high
 

Did all three problems occur at the same time??

RE: only on high
 

nope the wipers about three months ago no big deal rain x works better anyway, then the heat about three weeks ago, then the light just two days ago.

RE: only on high
 

Sounds like you have three separate problems with three different things and not related.

For example the headlights... did you check to see if the low beam part of the lamps weren't simply burnt out ?

The A/c heater ( assume you mean the fan ) could simply be the resistors ( coils).

The wipers could be the wiper control switch.