My GMC truck 1993 Sierra just had new headlights installed. But the high beams point into the trees. It seems both the high and low beam lights are in one enclosure. Can I adjust these down?

It shouldn't be the high/low beam switch, as that switches the high/low beam relays. One high beam relay supplies power for both sides, one for low beam, both sides. If you were to lose switch function or a relay, you would lose the high beams or the low beams, but not for just one side. It would be interesting to probe the fuses with a test light and see if you're getting power to and through them. If you are, the problem would be between the fuse box and the headlight, if your not getting power to the left head light fuses, the problem will be in the fuse box. Good luck!

See fuse for the headlight low beam or the head light low beam filament is bad change it after testing it on the battery

first off, be sure your low beams aren't both burned out. it happens all the time. next check your dimmer switch operation. (i'm betting on low beams burned out) good luck.

I think that many 1990s and even some 1980s GM vehicles with seemingly 4 headlight systems actually use only 2 at a time.

My 1990 Oldsmobile Cutlass Calais, for instance, had 2 high beams that went on independently of the 2 low beam lights when switched with the turn signal lever.

In the 1970s the GM vehicles had 4 headlight systems where all 4 headlights would go on, but they used sealed beams rather than the capsule lights that are used nowadays.

For instance, our 1976 Cadillac Seville has a 4 headlight system that lights up 4 headlights on the high beam mode.

Good luck on seeing at night with the current set up.

You need a new headlight switch my friend.

i had same p w 1996 gmc chgd bulb chgd switch checked wires in steering coloumfinmally went under dash where your left boot would be and wiggled a 3quarter by half inch relay and done it lite up all day of jackin 2sec fix

hi from uk provided you have checked bulbs are ok? then this fault may be the relay for the low /dipped beam has gone faulty if you check h/book you may find location of low beam relay there is relay for high and one for low beams if you find both relays ? try switching? this will confirm relay fault if you then have low beam but no high ? b4 you buy new relay other than tis the other possible fault may be the actual di/high beam stick control ?

go to stylinconcepts.com under the lighting section ther is a
HIGH 4 HEADLIGHT kit, this is very simple to install and will make both high and low beams work at the same time

Check voltage at the circuit box and test the high/low dimmer switch. Corrosion on a ground wire could also be the problem.

i would try replacing headlight switch....