Electrical Gurus: Dash lights not working

[Boston GN]

All the dash lights aren't working in my car. I checked fuses and everything is fine, I checked the bulbs and they look good. The idiot lights work, but not the "speedo" lights. What would cause this? What wiring should I be looking at and where does everything go with respect to that wiring.
TIA

 

[TR Custom Parts]

You don't have the dimmer switch all the way down do you???

 

[Boston GN]

haha, nope.
Only reason I figured this out (because I haven't driven the car yet) is because I was installing some gauges and went ot see if the dimmer worked on them. While doing this I found that 2 of the 3 INST LPS spots on the fuse panel don't work, dash lights don't work, heater/climate ones and the gear selector lights also don't work. Seems to me there has to be one thing that controls all these. Any ideas? I'm losing my mind.
Like I said, all my fuses are fine

 

[TurboShane]

Go to the junkyard and get a new dimmer switch. Worked for me. That's my best guess.

 

[Boston GN]

I will look into the switch. Problem is, my "extra gauges" (boost, tach, oil press etc) all work with the dimmer switch, but only work in one of the three INST LPS slots of the fuse panel.
Strange problem.
Thanks guys
Any more ideas?

 

[wlaukaitis]

Hey hi!,

Most of my lights didn't work either, this is what I did.

I had my cluster out to check a non-operational volts light, I checked all the continuity on the bulbs with my voltmeter on the beep mode. I found that most of the lights that didn't work had issues with the bulb to socket connection.

so I "adjusted" the contacts between said connections (Either slightly bending the contacts in the socket or on the bulb)

I still think I missed a few because it is awfully dark, but maybe thta is how it is supposed to be.

 

[Boston GN]

More findings: My "boost" led lights and the rpm led lights all work until I "turn on" my headlights, then those shut off. Does this lead to anything else? Any clues?

Thanks again guys


wlaukaitis: When I had my dahs apart trying to find out what the problem is, I checked all the bulbs and made sure everyhitng was seated properly.

 

[Wicked]

It could be a headlight switch or a bad ground from the gauge
lights. Usually if something goes out when you turn on the lights
its due to a bad ground. Good luck

 

[Boston GN]

Wouldn't by chance happen to know where that ground for those lights is?
What I really need is a wiring diagram

 

[salvageV6]

Factory Service Manual from Helms has all the wiring diagrams.

Re-check the tail lamps fuse and also the 5A INST LPS fuse.

 

[wlaukaitis]

Boston, Even when I took the socket out and check for continuity between the terminals, it was still bad, but see what else has been posted, I would look into a ground as well.

Strange as it is, my boost gauge started working when I changed my engine wiring harness

 

[wlaukaitis]

Grounds

These are the ground that the I/P lights use.


G104-Behind I/P To Left Of Steering Column
G107-Below RH Side OF I/P Near Shroud

S438-I/P Harness Above Fuse Panel - this is where everything splices together

Oh, I/P = instrument panel, took me a while to figure that out

As far as that connector, it could be anything. You were right with the grey being positive and black being negative. But since we both have it and it goes to nothing, I wouldn't sweat it.

Just for giggles, I would also check the ground that is on the firewall in the engine compartment, I had to drill a new hole. Don't know what it is for but who cares.