Electrical Issues

[SWDoodle]

This pickup is about to get the best of me! Have a 1992 GMC Sierra 1500 trying to get running decent again that just developed a bizarre electric issue. A week or so ago I put new lights, plugs, plug wires, and a new blower motor resistor in this old ranch pickup we had at the farm. It was needing some TLC. After I got all this stuff installed things were going great. Then the other day I started it and was going down the road and heard this loud buzzing from near the glove compartment. Next all my gauges started going haywire and lost my HVAC controls and power windows and locks. What's even more strange is that when I open the door the courtesy light is barely lights up. No fuses appear to blown and if I pull the courtesy fuse the HVAC will come back on! I did some trouble shooting and found that the buzzing sound is from the three relays from behind the glove compartment. Whenever I turn the fan on it buzzes. Thought it could be a bad relay but it will do it even if I put in a different one. Went under the hood to check voltage. Good voltage from the battery and alternator. Pickup runs fine lights work as they should even the under hood light is fine which is strange because the interior one only lights up about a 1/3 of normal. It appears to me for some reason I'm not getting full voltage to a portion of the electronics. Anything else I could check? Thought about new battery cables, checking grounds, etc, but looking for any other advice. This pickup ain't worth much as it's totally beat to heck but I'd like to keep it going as I can't find an used one anywhere with manual transmission that isn't worse than this one!

[Dnt]

Sounds like a circuit is shorted to ground. Is it possible that you skinned the insulation on one of the wires while you was in the there moving stuff around doing the blower resistor? Take it back apart and check your work.

Warning farm hand joke ahead. Maybe the ole truck needs a horse wuppin to get it in shape?

[SWDoodle]

I was thinking it was probably a short as well, but I am no expert by any means with wiring. Probably just have to end up taking it in I suppose if I can't find it soon. I just can't think what I might have done to nicked a wire in the process of working on it. However there definenately could have been a mouse or something chew on a wire and then I moved it just enough. Had strange deals like that happen before.

[Ronsoy]

The actuator is a good source of a short, try unplugging it to see if it works after that.

[Motor City Rick]

As old as this truck is, if you had a short, fusible links / high amp fuse would have blown. What you have is a "high resistance" ground. The moment you stated the "buzzing noises" behind the glove box and interior lights are at 1/3 power, dash going crazy, it tells me the ground for the body cab has a "high resistance connection" even though it might look good to you. Check "ALL" grounds between cab to motor, cab to frame rail, grounds that connect the main instrument panel wiring harness to the sheet metal behind the kick panels are secondary checks. If it's a outside ground connection, sand to a bright metal finish also look for green corrosion at the metal connector, if found, get /make new ground wire and apply a small amount of grease to reduce future corrosion. Don't forget to lightly tug on the cab grounds to see if the pull loose or anything changes.

[plastruck]

as a mechanic i can tell you that all of your dash ground wires go to the left side of the dash and it uses one bolt for the ground, check to see if maybe that bolt loosened up and the ground wires are loose, i ran into this problem on another chevy pickup and finally found the loose bolt on the ground wires, its under the dash near the door so easy to check and tighten if needed, this causes all the symtoms you mentioned.