Dash lights and dome light.

[Dennis O.]

My dash lights and dome light quit working the other day. Since I am old and arthritic, I want to minimize the things I have to look for under the dash. The dimmer function on the headlight switch has been "notchy" for a year or so now. Is that where I should start?

[Keith B.]

Re: Dash lights and dome light.

The headlight switch is where I would start.

[Bill K.]

Re: Dash lights and dome light.

I have an issue where dash lights don't work until I turn the switch all the way to manually activate the interior lights. No other issues with interior lights etc. I've already changed the switch and no change. Is there a wiring diagram anywhere the shows the dash light dimming circuit ? Is there a difference between coupe and convertible ? Maybe this will help both of us.

[William C.]

Re: Dash lights and dome light.

Dimming is accomplished via a wire-wound resistor in the switch itself. It is embeded into the ceramic near the end closest to the driver. Likely you have some oxidation in the contact that rides on the winding. Pull the switch out and clean it up.

[Bill K.]

Re: Dash lights and dome light.

Thanks Bill .. understand that. My original switch had a break in the wire wound resistor. Odd that the replacement would have the same issue but I will take it out and clean it up. Just wanted to make sure there wasn't a different electrical path for that function.

[Stephen L.]

Re: Dash lights and dome light.

While you have the switch out, connect an OHM meter to the dash light contact and make sure the rheostat (resistor) is varying in value.... as you turn the knob.

[Bill K.]

Re: Dash lights and dome light.

I've now got both switches (orig and replacement) on the bench. Anyone know which terminal is for the dash lights so I cant check the resistance ?

[Stephen L.]

Re: Dash lights and dome light.

REFER to the wiring diagram and the plug to find the appropriate pin. Looking at the wiring diagram the #16DG (dark green) feeds the dashlights thru a fuse, where the wire becomes gray and then out to the various lights. The switch should be in the headlamp "on" position, as you rotate the switch you should see a resistance change between the #12R and #16 DG contacts. Hope this is clear enough as electrical troubleshooting is hard to describe.

[John H.]

Re: Dash lights and dome light.

I've now got both switches (orig and replacement) on the bench. Anyone know which terminal is for the dash lights so I cant check the resistance ?

Bill -

Match up the cavity in the harness connector that has the dark green wire in it with the mating terminal on the switch, and that's what you're after; the green wire feeds the fuse block, and after the fuse, all the dash lights are on the same gray circuit.

[Stephen L.]

Re: Dash lights and dome light.

John, You are correct that the dash light wire color is grey; however the grey wire does not exist on the light switch in the AIM wiring diagram, because there is a fuse between the switch and the lights and the wire size and color change at that point.

[John H.]

Re: Dash lights and dome light.

John, You are correct that the dash light wire color is grey; however the grey wire does not exist on the light switch in the AIM wiring diagram, because there is a fuse between the switch and the lights and the wire size and color change at that point.

Steve -

You're right! Forgot about the green feed to the fuse block - corrected my original post.

[Bill K.]

Re: Dash lights and dome light.

Dennis, I feel like I hijacked this thread and apologize. Did you ever solve your light issue ?

[Dennis O.]

Re: Dash lights and dome light.

Dennis, I feel like I hijacked this thread and apologize. Did you ever solve your light issue ?

Bill don't worry about it; the more the merrier. And I have solved my problem. I don't drive after dark any more!

One last thing. The dome light does work sporadically, which points even more at the headlight switch in my mind.

[Dennis O.]

Re: Dash lights and dome light.

Well, I finally got around to getting and installing a new headlight switch, which fixed the problem. The old switch was OK, but when I separated the switch from the connector, there was a bunch of corrosion in the switch. I cleaned both the switch and the connector. I did use the new switch as it came in a GM box and on close inspection, looks exactly like the old one. Run your best parts, they say. The important thing I found is that this is not a difficult task; I had been dreading it because of the things I have read about C2 dashes and just looking at it is daunting The hardest part is getting the ferrule lined up properly with the threads on the switch when putting it all back together.

Now I'm going to attack my non-functional ammeter. Given the corrosion in the headlight switch, I bet there is a bad connection somewhere on it too. I have taken a close look and think it may be possible to get at it without removing the dash cluster, I'll try contorting this arthritic old body one last time too solve the last major problem with this car!

[Bill K.]

Re: Dash lights and dome light.

Dennis, glad you resolved your lights ! I also had a bad switch. The resistor in the switch was open at the point where the dome light engaged. New switch and all is now good !