Odd electrical problems

[mmeiers85]

Hello to all. I am an avid lurker of this site, on my fifth gmt400 truck, and have used this site for....literally everything. So I appreciate everything the members of this site do.

I'm having a few electrical problems I'm trying to sort out. My power locks do not work from any switch. I can hear the relay under the dash clicking, but no solenoids working. When I hit and hold the switch the dome lights come on.. and when I hold the passenger side the radio turns on.. also the DRL's work but when I turn the light switch on the headlights turn off.. The brights work though with the switch on.

Any ideas? I replaced the headlight switch to no avail, and I cleaned the chassis/cylinder head/firewall ground and replaced it. Are there any other grounds I could try? Any info is appreciated!

 

[Tech-GeeK1500]

What year is your truck? My power locks quit working on my 98 just the other day. Both switches are dead, no sounds or anything. Your problem does sound like a ground issue, maybe there is a ground in the cab? All your fuses look okay and your wiring from the doors aren't cut of chafed? I'm sure someone with chime in.

 

[mmeiers85]

It's a 99 Suburban. The rear switch doesn't work either. All fuses are good, accessory relay is working fine. I haven't checked the wiring in the doors yet, that will be the next endeavor.

 

[mmeiers85]

So I'm still working on this. I took the drivers door panel off today to check the wires. The solenoid is frozen, the end is broken off. The wire going to it is hot with the ignition on and not with the ignition off. Hitting the lock or unlock button briefly interrupts the power but that's it. With the ignition off the button only supplies power when I hit lock, unlock does nothing.

Any ideas? This is driving me crazy. Next step is to get a solenoid from the yard and see what it does.