Half dash lights not working - The 1947 - Present Chevrolet & GMC Truck Message Board Network

custom10nut · 11-22-2016, 09:37 PM

Yesterday when I checked, it looked like I had one bulb, on the right side of the speedo, not on. But tonight when I went to troubleshoot it, the only lights on are the gas gauge.
I put new bulbs in last week, and it didn't blow a fuse.
All the other lights that work off the headlight switch (new) work fine, and this has not been an issue before.
Any ideas?

**rustytruck50** · 11-22-2016, 10:26 PM

Printed circuit?
I have the same issue, but haven't had the chance to get into it....

custom10nut · 11-22-2016, 10:44 PM

I thought about that too. What confuses me is that it was working fine yesterday. I think I'm going to unhook it in the morning and clean the contact, like I should have done while I had it out last week.

**rustytruck50** · 11-22-2016, 11:06 PM

Strange as it sounds, if you've had any humidity or damp issues, it could have that quick of an issue...

**dmjlambert** · 11-22-2016, 11:25 PM

When I took out my instrument cluster, I polished the printed circuit contacts and the contacts on the bulb holders gently with Brasso and a Q-tip. It cleaned them up and made them shiny.

custom10nut · 11-22-2016, 11:32 PM

It looks like I'm going to take the dash back out and do a little cleaning.
Thanks for all the responses.
I'll update tomorrow

custom10nut · 11-23-2016, 10:17 AM

The electric grease is a great idea.
Is the circuit for the lights a series, because that would explain why they all stopped working at once.

**rustytruck50** · 11-22-2016, 11:31 PM

Sounds good...you might even want to put a small dab of dielectric grease on the tabs to help future tarnishing.

LongBox · 11-23-2016, 11:00 AM

The lights are wired in parallel, not series.

custom10nut · 11-24-2016, 10:38 AM

I toyed with it last night, and still no lights. The gauges all work so, it's got to be a connection issue. Now to find it.

**dmjlambert** · 11-24-2016, 11:00 AM

Check for broken brass tabs on your bulb holders, I had one or two of those bulb holders that were bad. New ones at Advance Auto Parts are fairly expensive at about $8 so that was annoying. But I bought it anyway because I was feeling like just getting it done that day.

I tested my instrument cluster while on the workbench, by attaching a ground strap between the negative of a battery and the metal of the cluster, then touching positive to pin 8 of the place on the printed circuit where the connector plugs in. You can't really use an alligator clip because the metal of the case is what the bottom jaw of the clip would grip, so it is easy to short out your 12V.

http://67-72chevytrucks.com/vboard/s...d.php?t=709847

If you need a printed circuit, I see new are available for online at various stores. Manes Truck Parts has used ones for $25.

custom10nut · 11-24-2016, 02:57 PM

All my tabs ar good, I just took them all out yesterday, and cleaned them. What I didn't do was clean the contact points on the printed circuit. I'm gonna take it out and most likely get a new printed circuit

11-22-2016, 09:37 PM	#1
custom10nut Registered User Join Date: Apr 2015 Location: East Tn (In the heart of the Smoky Mtns) Posts: 1,867	Half dash lights not working Yesterday when I checked, it looked like I had one bulb, on the right side of the speedo, not on. But tonight when I went to troubleshoot it, the only lights on are the gas gauge. I put new bulbs in last week, and it didn't blow a fuse. All the other lights that work off the headlight switch (new) work fine, and this has not been an issue before. Any ideas?

11-22-2016, 10:26 PM	#2
rustytruck50 Senior Member Join Date: Feb 2011 Location: Papillion, Ne Posts: 897	Re: Half dash lights not working Printed circuit? I have the same issue, but haven't had the chance to get into it.... __________________ -Doug '05 RCSB Sierra 2WD '71 Sierra 2WD Longbed '98 Silverado K1500 Xcab...sold '72 Highlander"Raymond"...sold

11-22-2016, 10:44 PM	#3
custom10nut Registered User Join Date: Apr 2015 Location: East Tn (In the heart of the Smoky Mtns) Posts: 1,867	Re: Half dash lights not working I thought about that too. What confuses me is that it was working fine yesterday. I think I'm going to unhook it in the morning and clean the contact, like I should have done while I had it out last week.

11-22-2016, 11:06 PM	#4
rustytruck50 Senior Member Join Date: Feb 2011 Location: Papillion, Ne Posts: 897	Re: Half dash lights not working Strange as it sounds, if you've had any humidity or damp issues, it could have that quick of an issue... __________________ -Doug '05 RCSB Sierra 2WD '71 Sierra 2WD Longbed '98 Silverado K1500 Xcab...sold '72 Highlander"Raymond"...sold

11-22-2016, 11:25 PM	#5
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,646	Re: Half dash lights not working When I took out my instrument cluster, I polished the printed circuit contacts and the contacts on the bulb holders gently with Brasso and a Q-tip. It cleaned them up and made them shiny.

11-22-2016, 11:32 PM	#6
custom10nut Registered User Join Date: Apr 2015 Location: East Tn (In the heart of the Smoky Mtns) Posts: 1,867	Re: Half dash lights not working It looks like I'm going to take the dash back out and do a little cleaning. Thanks for all the responses. I'll update tomorrow

11-23-2016, 10:17 AM	#7
custom10nut Registered User Join Date: Apr 2015 Location: East Tn (In the heart of the Smoky Mtns) Posts: 1,867	Re: Half dash lights not working The electric grease is a great idea. Is the circuit for the lights a series, because that would explain why they all stopped working at once.

11-22-2016, 11:31 PM	#8
rustytruck50 Senior Member Join Date: Feb 2011 Location: Papillion, Ne Posts: 897	Re: Half dash lights not working Sounds good...you might even want to put a small dab of dielectric grease on the tabs to help future tarnishing. __________________ -Doug '05 RCSB Sierra 2WD '71 Sierra 2WD Longbed '98 Silverado K1500 Xcab...sold '72 Highlander"Raymond"...sold

11-23-2016, 11:00 AM	#9
LongBox Registered User Join Date: Sep 2016 Location: Vancouver BC Posts: 784	Re: Half dash lights not working The lights are wired in parallel, not series. __________________ Rick -69 GMC 910 Long Box, 350 -98 Chev Silverado 1500, 350 Vortec 4L60e -08 Mustang GT Convertible

11-24-2016, 10:38 AM	#10
custom10nut Registered User Join Date: Apr 2015 Location: East Tn (In the heart of the Smoky Mtns) Posts: 1,867	Re: Half dash lights not working I toyed with it last night, and still no lights. The gauges all work so, it's got to be a connection issue. Now to find it.

11-24-2016, 11:00 AM	#11
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,646	Re: Half dash lights not working Check for broken brass tabs on your bulb holders, I had one or two of those bulb holders that were bad. New ones at Advance Auto Parts are fairly expensive at about $8 so that was annoying. But I bought it anyway because I was feeling like just getting it done that day. I tested my instrument cluster while on the workbench, by attaching a ground strap between the negative of a battery and the metal of the cluster, then touching positive to pin 8 of the place on the printed circuit where the connector plugs in. You can't really use an alligator clip because the metal of the case is what the bottom jaw of the clip would grip, so it is easy to short out your 12V. http://67-72chevytrucks.com/vboard/s...d.php?t=709847 If you need a printed circuit, I see new are available for online at various stores. Manes Truck Parts has used ones for $25.

11-24-2016, 02:57 PM	#12
custom10nut Registered User Join Date: Apr 2015 Location: East Tn (In the heart of the Smoky Mtns) Posts: 1,867	Re: Half dash lights not working All my tabs ar good, I just took them all out yesterday, and cleaned them. What I didn't do was clean the contact points on the printed circuit. I'm gonna take it out and most likely get a new printed circuit



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