Where is automatic light switch on my 2004 buick rainer cxl model suv

The Headlight are automatic, try the turn signal switch.

On this website you find fuse box diagram and description for Buick Rainer (2004)

http://www.carknowledge.info/buick-rainer-2003-2006-fuse-box-diagram

Best if you open the plastic and use voltmeter on the reverse light contacts. Check fuses or worse the reverse switch on the gear handle...

I have seen alot of the rear shocks that leak on these vehicles... also there is a nother not so common problem of the solinoid failing open and letting the air drain back through the compresor... I would try and spray the shocks around the rubber boot with a soapy water solution and check for bubb;es indicating a leak.

drivers front under hood wheel well area battery area

Switch relay #45 with relay #46 next time your low beams go out, do you have lights again? If so, get a new relay.

CHECK ALL FUSES TO IGNITION SWITCH + BCM.CHECK FUSES TO POWER WINDOWS AND DOOR LOCKS.

If the brake pads are cheap ones there is your problem. cheap pads can squeal, chatter, and wear out really fast

Pretty common problem with these. Here's a guide to learn how to fix GM instrument clusters yourself, I used it to fix mine and it worked great.How to guide for Rendezvous instrument cluster repair

REPLACE UNLOCK MOTOR.