Dash lights are out...all of 'em...any clues? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

thecatseye66 · 05-12-2005, 07:29 PM

The dash lights on my 68 aren't working. The fuse that goes to the instrument panel is good and the voltage reads 12.2 at the fuse. I can also adjust the voltage at the fusebox using the dimmer twist on the light switch.

Are the dash lights wired in succession like a christmas tree? If one goes out does the circuit break?

Any other ideas?

farside847 · 05-12-2005, 07:40 PM

No, they are wired to light even if one it out.

It could be all bad bulbs. I have seen it myself.

vtblazer · 05-12-2005, 08:05 PM

Check for a good ground.

pritch · 05-12-2005, 08:48 PM

This break in the ground circut in my dash was the problem with the gas gauge, but it also took out all the lights downstream of the break. It looked like care was not taken when someone changed the light.

Ratpowerd67 · 05-12-2005, 09:11 PM

turn the knob that dimmes the dash lights ( headlight knob ) try turning it back and forth while while shakeing it a little. sometimes they stick .....if that dosent work , it could be the dimmer itself................hope this helps

thecatseye66 · 05-12-2005, 09:21 PM

Thanks guys--
The dimmer works fine because I can watch the readoout on the digital voltmeter I hooked up to the fuse fluctuate when I turn the switch. I'll check for a break in the circuit while I'm checking the lights and make sure the ground is clean.

70 shorty · 05-12-2005, 09:34 PM

When all my dash lights didn't work, it turned out to be the headlight switch. $10 for a new one and about 5 minutes to put it in. I don't know enough to know if your troubleshooting eliminates the switch or not, though.

thecatseye66 · 05-13-2005, 02:31 AM

Thanks Shorty--
That might be it after all. I don't think my dimming of the lights test with my voltimeter was right last night because I couldn't duplicate it tonight. I will pull the light switch out of the green c-10 and try it like you said. I know that one works.
I checked the circuits in the panel -- all dead in the light pods but the blinker pods work fine. No breaks in the circuits and its grounded plenty.

Does anyone know which color wire in the panel plug supplies power to the printed circuit for the panel lights? I'd like to check that plug and test that wire if the new light switch doesn't cure it.

05-12-2005, 07:29 PM	#1
thecatseye66 '68 C-20 396 CST CC Join Date: Mar 2005 Location: Spokane, WA Posts: 454	Dash lights are out...all of 'em...any clues? The dash lights on my 68 aren't working. The fuse that goes to the instrument panel is good and the voltage reads 12.2 at the fuse. I can also adjust the voltage at the fusebox using the dimmer twist on the light switch. Are the dash lights wired in succession like a christmas tree? If one goes out does the circuit break? Any other ideas?

05-12-2005, 07:40 PM	#2
farside847 Registered User Join Date: Feb 2005 Location: Bay Area, California Posts: 995	No, they are wired to light even if one it out. It could be all bad bulbs. I have seen it myself. __________________ 1971 Chevy C10 Shortbed Stepside, 307v8 3-on-the-tree

05-12-2005, 08:48 PM	#4
pritch Registered User Join Date: Mar 2004 Location: Hoytsville, Utah Posts: 3,365	This break in the ground circut in my dash was the problem with the gas gauge, but it also took out all the lights downstream of the break. It looked like care was not taken when someone changed the light. __________________ '68 Panel Project Boogie Chillin' '68 C-10 Ol' Green

05-12-2005, 09:11 PM	#5
Ratpowerd67 Registered User Join Date: Aug 2002 Location: Trenton ,Texas Posts: 328	turn the knob that dimmes the dash lights ( headlight knob ) try turning it back and forth while while shakeing it a little. sometimes they stick .....if that dosent work , it could be the dimmer itself................hope this helps Last edited by Ratpowerd67; 05-12-2005 at 09:13 PM.

05-12-2005, 09:34 PM	#7
70 shorty Where's my beer? Join Date: Oct 2004 Location: Glen Allen, VA Posts: 1,772	When all my dash lights didn't work, it turned out to be the headlight switch. $10 for a new one and about 5 minutes to put it in. I don't know enough to know if your troubleshooting eliminates the switch or not, though. __________________ 70 C10, shortstep, .30 over 250,Hurst shifted 3 spd parts hauler. Holley 390, Clifford Intake, Header, ported cylinder head, unknown bigger cam. 79 Corvette L82, 4 spd, black, red interior, headers, flowmasters, and unkown bigger cam. '03 Grand Cherokee Laredo, 4.0 4x4 daily driver. 165K miles, and runs great '08 Tahoe LTZ 4x4 155K

05-12-2005, 08:05 PM	#3
vtblazer Registered User Join Date: Oct 2003 Location: Central Vermont Posts: 8,538	Check for a good ground.

05-12-2005, 09:21 PM	#6
thecatseye66 '68 C-20 396 CST CC Join Date: Mar 2005 Location: Spokane, WA Posts: 454	Thanks guys-- The dimmer works fine because I can watch the readoout on the digital voltmeter I hooked up to the fuse fluctuate when I turn the switch. I'll check for a break in the circuit while I'm checking the lights and make sure the ground is clean.

05-13-2005, 02:31 AM	#8
thecatseye66 '68 C-20 396 CST CC Join Date: Mar 2005 Location: Spokane, WA Posts: 454	Thanks Shorty-- That might be it after all. I don't think my dimming of the lights test with my voltimeter was right last night because I couldn't duplicate it tonight. I will pull the light switch out of the green c-10 and try it like you said. I know that one works. I checked the circuits in the panel -- all dead in the light pods but the blinker pods work fine. No breaks in the circuits and its grounded plenty. Does anyone know which color wire in the panel plug supplies power to the printed circuit for the panel lights? I'd like to check that plug and test that wire if the new light switch doesn't cure it.

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