C3 Gauges and Tachometer, HELP!
Thread Starter
8th Gear
Joined: Oct 2022
Posts: 8
Likes: 0
From: Los Angeles
C3 Gauges and Tachometer, HELP!
Hi Folks,
I bought a 1978 Silver Anniversary with only 12k miles a couple months ago. Everything except for the Tachometer worked when I got it, including the clock! I had a vintage radio installed with bluetooth and XM. The radio installer broke my clock. Good news they paid for a new one. I opened up the center console replaced all of the non-workig lights and the paper circuitboard. I also replaced the circuit board on the Tach. That didn't work -- I plugged the tach wire directly to the distributer and that worked. Drove around with a working tach for 3 weeks. When I installed the clock and was re-installing the gauge cluster I noticed that all of the working gauges are not working now, including the tach! Only thing that works now is the clock! What did I do wrong? Should I have disconnected the battery before re-installing the gauge cluster? Did I burn out the two new circuit boards? Did I blow a fuse? This really sucks. Back to square one. I thought I was doing a great job. I'm not a mechanic or an electrician.
Can someone help me? Tell me what I did wrong? Thank you!
Best,
Ted
I bought a 1978 Silver Anniversary with only 12k miles a couple months ago. Everything except for the Tachometer worked when I got it, including the clock! I had a vintage radio installed with bluetooth and XM. The radio installer broke my clock. Good news they paid for a new one. I opened up the center console replaced all of the non-workig lights and the paper circuitboard. I also replaced the circuit board on the Tach. That didn't work -- I plugged the tach wire directly to the distributer and that worked. Drove around with a working tach for 3 weeks. When I installed the clock and was re-installing the gauge cluster I noticed that all of the working gauges are not working now, including the tach! Only thing that works now is the clock! What did I do wrong? Should I have disconnected the battery before re-installing the gauge cluster? Did I burn out the two new circuit boards? Did I blow a fuse? This really sucks. Back to square one. I thought I was doing a great job. I'm not a mechanic or an electrician.
Can someone help me? Tell me what I did wrong? Thank you!
Best,
Ted
Burning Brakes
Joined: Oct 2022
Posts: 1,063
Likes: 170
From: Buckeye Lake, OH
When you say your gauges don't work, what do you mean? Are they showing ANYTHING/any deflection? Is there any difference between key on and key off?
When you pulled the cluster, could you have possibly disconnected the Ground wire? Ground is very important, as it completes the circuit.
It sounds, to me, that you disconnected the Ground wire.
When you pulled the cluster, could you have possibly disconnected the Ground wire? Ground is very important, as it completes the circuit.
It sounds, to me, that you disconnected the Ground wire.
Thread Starter
8th Gear
Joined: Oct 2022
Posts: 8
Likes: 0
From: Los Angeles
I may have disconnected the ground wire. I'm getting nothing from the gauges. Clock continues to run. And why does my Tach not work now, too? How can I find the ground wire? I only have connected the big wiring harness to the center of the cluster. Thats what I connect and disconnect.
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
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Or simply blew a fuse because something touched that shouldn't have. Always disconnect the battery when working on anything electrical.
Thread Starter
8th Gear
Joined: Oct 2022
Posts: 8
Likes: 0
From: Los Angeles
Since I'm new to this I'm not going to beat myself up over mistakes, but I had a hunch that I should've done that. Should trust my gut. Thanks. Hopefully If I replace the fuse the guage cluster and the tachometer will work again. Ugh. Didn't know they were connected but maybe they run off the same fuse?
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