Speedometer and Tachometer Lights quit working
Thread Starter
4th Gear
Joined: Dec 2014
Posts: 4
Likes: 0
From: TX
Speedometer and Tachometer Lights quit working
I have a 1980 C3 that the speedometer lights and tachometer lights have quit working. I have turn signal lights, and the emergency brake indicator lights, and all of my center console huge cluster lights are working. The first time they quit working, I change the fuse and they came on. They worked for a while, and then quit again about a month later. I changed the fuse again, and nothing. I replaced the bulbs, nothing. The old bulbs I took out and tested them, and they worked which eliminated any bulb issues. Where do I go from here?
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
More than likely there is an issue with the printed circuit board on the back of the speedo tach housing. The lamps on the center bezel are on the same circuit and since you stated they are working, this pretty much isolates it to the circuit board, or a short in the wire running to the pcb connector. .
Pull the housing out of the car (directions are below) and check the printed circuit as well as the fingers on the connector and the fingers that are on the board to make connection. These fingers have a long history de-laminating and coming loose from board.
make sure the terminals on this connector are touching the correct fingers on the pcb.
Corvette Speedometer and Tach Housing Removal Instructions 1978-1982
Pull the housing out of the car (directions are below) and check the printed circuit as well as the fingers on the connector and the fingers that are on the board to make connection. These fingers have a long history de-laminating and coming loose from board.
make sure the terminals on this connector are touching the correct fingers on the pcb.
Corvette Speedometer and Tach Housing Removal Instructions 1978-1982
Race Director
Joined: Apr 2009
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From: Charlotte NC
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
http://willcoxcorvette.com/product_i...ducts_id=25310
43.00 in the forum special section or site.
Willcox
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,851
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
I think your issue is that the pcb came un-laminated. When this happens it is possible for the copper trace to fall and touch.
The connector and connector terminals look fine, I don't see any sign of an issue with it.
But I would make sure that each terminal is powering up correct. Make sure the grounds or the signal terminals do not have power on them. It would only take a second with a multimeter.
A new board will probably solve your problem. If/when you get one, removal of the tach stud clips can be done by gently placing a flat tipped screw driver under the back side tang and twisting. Don't do so with enough force to bend or break it, and be careful... they are not cheap and I don't have very many of them left in stock.
Willcox.
The connector and connector terminals look fine, I don't see any sign of an issue with it.
But I would make sure that each terminal is powering up correct. Make sure the grounds or the signal terminals do not have power on them. It would only take a second with a multimeter.
A new board will probably solve your problem. If/when you get one, removal of the tach stud clips can be done by gently placing a flat tipped screw driver under the back side tang and twisting. Don't do so with enough force to bend or break it, and be careful... they are not cheap and I don't have very many of them left in stock.
Willcox.
Last edited by Willcox Corvette; Dec 28, 2014 at 03:05 PM.
Thread Starter
4th Gear
Joined: Dec 2014
Posts: 4
Likes: 0
From: TX
I ordered the printed circuit board from Willcox Corvette, installed it, and WALA! I relaxed my bulbs with LED so I had to reverse a few but everything is now lit up and shining bright! You guys are awesome and I will definitely be returning should I need any more advice, instructions, or parts (which is likely)!!
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