I have a 1999 suburban 5.7 and the the a/c compressor will not shut off. The only way I can get the compressor is shut off is to pull the relay under the hood. The relay is energized I know this because you can hear it click when you plug it in. I swapped it with h the horn relay and still won't shut off. So I know it's not a sticking relay. it's also not in defrost mode. I have pulled out the control in the dash and it still runs. It seems that the signal from the VCM to energize the relay is always on. Please help

SOURCE: 1999 GMC Suburban DRL Work - Headlights/Highbeams Do Not

go to autozone the can help you if you have one they do a lot of things fore nothing including clearing codes

SOURCE: 1995 Suburban HVAC - no defrost or vent only floor mode

I have a 1500 chevy picup that did the same thing the control panel (blower, temp, and selector) is what was the problem with mine replaced that and fixed it. Very easy to chg.front of dash pops off control panel pops out 1 plug ( yours may have 2 plugs)
pop back in and your done.

SOURCE: 2003 Suburban heater fan will not working.

1st attach a test light from negative battery terminal to voltage wire at blower motor and test for power
2nd attach a test light from positive battery terminal
to ground wire at blower motor and test for ground

if both tests light the test light suspect blower motor
if no ground suspect resistor
if no power suspect short in voltage wire
these vehicles are known for burning out the wire
connection at the blower motor look for discoloration
at the plug
i hope this helps

SOURCE: My 1999 Chevy suburban is stuck in 4 wheel drive.

I have seen more than my fair share of the motors binding or hanging up on the transfer case if this is the push button electronic shift 4WD.Most of the time they only actup when it gets cold outside,most fixes have been total transfercase motor and board assembly but I have had some luck with tapping on the motor with a hammer while the vehicle was running at normal operating temp.,and the truck in neutral with someone pressing the switch and there foot on the service brakes so you don't get run over.GOOD LUCK

SOURCE: horn does not sound

horn is under the hood. usually right against the grill or mounted on fender well. fuses for horn can be under the dash, or in fuse panel under the hood.