Weird problem with running and cab lights.

[Willis]

1987 Chevy Silverado.

I was driving down the road the other night and all of a sudden, all my dash lights went out, and the dome and floor lights turned on. The dome light is dim, and I can still manually turn it on by twisting my light pull out switch to normal brightness. But it won't turn off unless my headlights are turned off.  Then someone follows me to a gas station to tell my my tail lights are out, but my brakes and signals all work, even signals on the front.

I've checked all the fuses, and I even replaced the whole switch in the dash, but to no avail, the problem still exists..

So here's what's working and not,

Working;

Headlights
Brake lights
All turn signals

Not working;
Front running or "parking lights" ( orange ones )
Rear running lights
Dash lights/gauges
Radio lights

Randomly came on;
Dome light
Floor light ( which never worked before )

Hope this is clear enough to help me, if not I'll do the best I can to answer any other questions..

I really need to fix this as I leave for work early in the Am when it's dark and come home late when it's dark.. Not trying to cause an accident or get a ticket.

Thanks for any helps everyone!

[Irish_Alley]

seams like a faulty headlight light switch

[Willis]

seams like a faulty headlight light switch

That's what I thought, so I replaced it, and nothing has changed. 

[zieg85]

Check the body grounds.  An intermittent ground does really weird stuff

[Captain Swampy]

It sounds like a ground issue to me. Clean both ends of your battery cables even if they don't "look" bad. There is a ground from the battery to the fender and one from the passenger side of the engine to the firewall, clean them. Under the dash near the parking brake is a main ground that most  in cab stuff connects to. Take it off and clean the back side and where it attaches. Somewhere on the back of the vehicle there should be a ground for the lights. My guess is the one on the back or the battery cables and engine compartment grounds will fix this.

There is a connector from the tail lights to the main harness at the rear of the vehicle that causes problems. Unplug it and try to clean it or cut it out.

[86HighSierra]

I'm betting it's the ground behind the tail lights. I know mine was rusted in two and was causing goofy stuff like that . Mine was on driver side. I think we have one on passenger side too.

[Willis]

About to dive into it tonight.. Now, as far as I can see, terminals are fine except on the drivers side battery which I don't believe powers anything. I can't find the "ground" that's by the parking brake, and I don't see anything bolted or screwed to the body under there. I'm about to pull the tail lights out of it and look for the ground you were talking about.

[Willis]

Ok as for the taillight ground, there's only one on the drivers side, but not one on the left side.

[gunrac]

Ok as for the taillight ground, there's only one on the drivers side, but not one on the left side.

That was the only one i had on the tail end, D Side. That is the left side.
Helpful hint: Describe your sides of your vehicle as if your setting behind the steering wheel.

[hatzie]

You've got a mix of symptoms.  The first place I'd look is the headlamp switch.

US Driver side is the LH side...  There's a ground on the sheet metal behind the fleetside tail lamp on the LH side.  There is no ground behind the RH fleetside tail on most of the squares.  This should only affect the tail lamps.

The dash grounds are above the E-brake assembly on the side kick panel...  I have seen a few attached to the E-brake mounting bolts.  This will make the dash lamps and courtesy lamps/dome lamp act strangely or not work at all. 
The courtesy lamps and dome coming on randomly with the door closed is probably the doorjamb switch but it could be the headlamp switch too.  These are grounded to the main dash ground along with the gauges and warning lamps.

Check the front parking light / headlight grounds on the radiator support below and toward the radiator from the battery trays. This will make the forward lamps act strangely.

The dash lamps, gauges, and parking lamps all run off the same fuse on several years.