Steel_Venom

I replaced my headlight switch (because it felt totally worn out) with a new one. Now, my brights no longer come on...maybe that should be a different thread...

But also my dash lights (center cluster & speedo/tach) are on but are super dim. I converted to LED lights, and some of the other LEDs are super bright, so I know they're just dim. They also like to flicker.
I've wiggled the plug on the back of the center cluster gauges.
Every now and then if I move the center cluster unit around *just* right they'll all light up bright for a split second.

I replaced all my fuses with new ones lately, and just to be safe re-checked them all for continuity and found no problems.

I figure it's a grounding issue or corrosion but not sure where to look/check. Any suggestions would be much appreciated

DUB

Brights are NOT controlled by the headlight switch....they are controlled by your dimmer switch which is on your column...via pulling back on the turn signal lever. AND it depends if you are getting BATTERY voltage to your dimmer switch.

The reason your dash lights are dim is you do not have good contact...where that is...I can not tell you. You have to verify when the headlight switch is pulled that you are getting battery voltage to the area needed. SO the use of a volt meter is needed and NOT a test light...which can not tell you voltage values.

Hopefully your headlight switch was the correct one with the grounding terminal on the side.

You did not write if you have LOW BEAMS.

AND also remember that just because you replaced the fuses does not mean much at all...because if your have voltage drops at the fuse panel...'things' will not work correctly if you do not have at least 12 volts.

DUB

Steel_Venom

Haha...well I feel silly now....yeah the brights are on the column not the dimmer switch. So disregard that part of the post as that works fine. (most of the labeling is worn off on my poor C3 so I just push, pull, and turn ***** to see what they do...most don't do anything )

Does anyone have a wiring diagram for the dimmer switch? It'd be really helpful to know what wire does what!

I found this thread, which shows how you can bypass the dimming feature of the dimmer switch and provide full power to the dash lights. Seeing as how I installed LED lights which basically only work at full power, this seems like a good possible fix.
https://www.corvetteforum.com/forums...-rheostat.html

I don't think the rheostat itself is the problem anymore; my old one was very loose feeling. This one is very tight and you can feel it as you turn the dimmer switch.

I'll try the bypass this week (hopefully!). I'll also take some voltage readings.

DUB

In you post you wrote that you can move the center cluster to a point and the lights light up. That is telling me that it is not in your headlight switch.

The dash lights will not be able to be dimmed...they will either be ON or OFF....unless you add another components to allow the LEDS to be dimmed at your gauges.

DUB

Steel_Venom

Yeah, I agree my switch is most likely good.

Right, I agree the LEDs aren't dimmable with the switch, the problem is that they are very flickery and dim. Especially compared to warning lights (low fuel, GEN, etc). So, that's why I know there's a weak electrical connection.

DUB

Do not be surprised that you might have broken strands of copper in the wire itself ( usually right at the crimp point) and the insulation is still looking good and intact.

DUB

Steel_Venom

Got if fixed! Thanks for reminder to check the fuse.

At the switch, I had 11.8v coming in on the brown wire, and 11.8v going out on the green wire. (may have wire color backwards...also my battery was nearly dead again). So, I knew rheostat was good. When I checked a light, I only had 3.8v, and checked the plug/wiring harness pins, still only 3.8v. So, I knew there was problem with the wiring going from rheostat to the gauge.

It was the fuse...I had replaced & tested all other fuses in the fuse box except this one. I didn't even know it was in there.... Check out the attached pic of it when I removed it. New fuse worked great. 11.8v going to lights, and they light up very brightly.

So for any future readers, I had 2 problems:
1- Rheostat was worn out. I could wiggle the light **** & it would make the lights come on & off (dim as they were).
2- Fuse was corroded badly.

EDIT: Also, brights work fine. Helps to use the correct switch to turn them on. I really need an owners manual =P

DUB

NOT an owners manual...but rather a Factory Service Manual.

DUB

Steel_Venom

So does anyone know what else is on the Instrument Lamps fuse besides the dash lights?

My instrument lamps fuse keeps blowing every time I turn them on. I unplugged the center console gauges harness, the speedo/tach cluster, the light at the shifter, and both plugs that go to wipers, and the fuse still blows as soon as i turn dash lights on.

So either my new switch is putting out too much power, or something else is on this fuse that I'm missing...

What's weird is that all my dash lights worked fine on my last update, then when I went to work on it yesterday I had this problem. (hadn't touched the car since last update so not sure what would change)

mauiwilly

Soooooooo, question to all.
All my dash / gauge lights are very dim as well...
But all the bulbs are working and all at same level of brightness.( or UN brightness)
Do I start by replacing the headlight switch/dimmer (rheostat) it is the original....
Or is it the actual bulbs ?

Thanks !

Steel_Venom

Here's what I did to find the problem & fix:

Used a multimeter set to 12v DC & measured one of the wires off the rheostat that powers the lights. (Forget which one off top of my head...can check & tell you if needed)
Got a good 12v reading off that wire
This indicates the rheostat is not the *main* problem & is putting out proper voltage

Went to several various dash lights and took readings.
Got like 2-3v
Realized something was amiss- I was getting massive voltage drop from the rheostat to the lights.

Turns out my fuse was horribly corroded (pics of it a few posts up). I thought I replaced all my fuses already but this one was hiding way up in the fuse box & I honestly didn't see it.

After the new fuse, I still had 12v on Rheostat and now had 12v at my dash lights!

But my Rheostat was very loose and wobbly...I could tell it was totally worn out, so I replaced it too. Now my headlights are way brighter & my dash lights work consistently.

mauiwilly

Thanks Steel Venom !
Good to know......
I'm thinking its my dimmer switch...as its kinda loose like yours was...
I'll put a meter on it and see what kinda voltage I get...
I have the AIMS Manual as well as the shop manual for my car so all the wiring diagrams are available to me...
I would recommend "both" of them to you...they are "invaluable" !!