1990 Silverado instrument, radio, tail lights all out

CAKMN48

New member
Joined
May 1, 2024
Messages
4
Reaction score
1
Points
3
On my ancient truck, suddenly all of my instrument cluster lights, radio lights and tail lights suddenly quit working, as well as the alarm warning that I've left my headlights on.

I haven't been able to find anything to help me zero in on what fault might have caused this, although I did find some mention that there is some fault that does cause this particular symptom, but there were no specifics for me to work with.
 
I assume you checked fuses?
Well, I thought I had checked them all. After posting, I decided to check them again. Lo and behold, I found one bad 20A, replaced it, and now ALL MY LAMPS WORK as they should.

I may have missed that one fuse the first time through when I thought all the fuses were good.

For anyone else who finds this particular pattern of lamps and the warning alarm not functioning, check the 20A fuse labeled PARK LPS.

I have no clue why this particular fuse might cause this particular issue. The owner's manual says that the circuits protected are: Horn Relay, Horn Feed, Cigar Lighter, Park Lamps.

Strangely enough, I discovered that my previous Silverado – a 1992 that still sitting out back – had the same fuse blown. I thought I was going to pull that fuse to replace the bad one in my 1990. Instead, I pulled out a different 20A fuse to use as a replacement. But my '92 (before it died) did not exhibit the same lamp issue as my '90 – In the '92 the radio and the dome lamp quit working and the wiper motor was struggling intermittently, while the other electrical stuff seemed to be doing fine.
 
Last edited:
HELP ! — I need to revive this thread because my problem is still not solved. There apparently is an intermittent SHORT somewhere in the electrical system that keeps blowing the 20A fuse labeled PARK LPS.

As previously noted, the owner's manual says that the circuits protected are: Horn Relay, Horn Feed, Cigar Lighter, Park Lamps. As an update, I have noticed that both front and back parking lamps fail when the fuse blows, not just the tail lights. And the Radio lights also fail. I've also noticed that the dimmer control for the dash lights fails when the fuse is blown, which leaves the clock and heater lights on at full brightness.

After replacing the fuse, I drove for about half a block distance out our alley. There are some potholes at the exit of the alley. When I went through a couple and the truck was jerked around the fuse immediately blew. I replaced the fuse and tried to find the location of the short, but couldn't actually see any likely bad spots or signs of sparking. I drove out the alley again, through the potholes, with absolutely no problem and drove about three blocks, turned around, and drove back to my front driveway where I turned the lights off and then back on and they still kept working fine. After unloading something from the truck, I restarted it and the lights were still working fine as I drove back around and into the alley — but as soon as I again hit a couple of potholes, the fuse immediately blew.

I searched more and, remembering the electrical stuff in the doors for the locks and power windows, I thumped against the inside of the driver's door, which caused the fuse to blow after quite a bit of thumping, which made me think that the short must be inside the door. So, I pulled the panel off and examined every bit of wiring in there, wiggling it all around in various ways, operated the lock and window controls, but nothing I did caused the fuse to blow, nor could I see any problem that would cause a short or any evidence of sparking. I put it all back together, started the truck, and just before I had a chance to shift and start driving, the fuse blew again.

I've checked over everything I can think of – short of electrical wiring and connections inside the steering column housing (which I have wiggled and jiggled plus worked the multi-switch lever, all without blowing the fuse) – and still have not found a short anywhere, under the hood, under/behind the dash, at the parking lamps. What should I do next?
 
Have you considered the door wire harness where it passes from the door to the body of the vehicle?
 
Have you considered the door wire harness where it passes from the door to the body of the vehicle?
Yes, I did look at that and didn't see any problems with it. And further thumping on the door and opening/closing the door failed to blow the fuse.
 
Back
Top