C3 Electrical Troubleshooting
Thread Starter
3rd Gear
Joined: Nov 2021
Posts: 3
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C3 Electrical Troubleshooting
I'm having an issue with the wiring in my 72 C3. Currently the radio, wipers, and TCS are not getting power. The car has all new harnesses, AC and blower motor work, all lights and turn signals work. Probing around with a test light, there does not seem to be power at the radio fuse, and the TCS fuse on the drivers side panel. Anyone have any ideas one where to start looking or how to track down the source of this issue? The car starts and drives but the radio does not work at all, and the wipers do not operate. All other fuses in the block have power except for those two.
Melting Slicks
Joined: Apr 2001
Posts: 2,030
Likes: 363
From: Lubbock Texas
I'm having an issue with the wiring in my 72 C3. Currently the radio, wipers, and TCS are not getting power. The car has all new harnesses, AC and blower motor work, all lights and turn signals work. Probing around with a test light, there does not seem to be power at the radio fuse, and the TCS fuse on the drivers side panel. Anyone have any ideas one where to start looking or how to track down the source of this issue? The car starts and drives but the radio does not work at all, and the wipers do not operate. All other fuses in the block have power except for those two.
Welcome to the forum.
First, double check a couple of things. Sometimes the terminals holding the fuse gets tarnished or corroded and prevents the fuse from making good contact. I had this issue when I first picked up my '73. I had to use a small wire brush and a sharp pointed knife to clean every terminal in my fuse block (disconnect the battery first). Also check the fuses themselves. Some times they'll look good but still be bad.
Good luck,
DC
Thread Starter
3rd Gear
Joined: Nov 2021
Posts: 3
Likes: 0
Welcome to the forum.
First, double check a couple of things. Sometimes the terminals holding the fuse gets tarnished or corroded and prevents the fuse from making good contact. I had this issue when I first picked up my '73. I had to use a small wire brush and a sharp pointed knife to clean every terminal in my fuse block (disconnect the battery first). Also check the fuses themselves. Some times they'll look good but still be bad.
Good luck,
DC
First, double check a couple of things. Sometimes the terminals holding the fuse gets tarnished or corroded and prevents the fuse from making good contact. I had this issue when I first picked up my '73. I had to use a small wire brush and a sharp pointed knife to clean every terminal in my fuse block (disconnect the battery first). Also check the fuses themselves. Some times they'll look good but still be bad.
Good luck,
DC
Melting Slicks
Joined: Feb 2018
Posts: 2,327
Likes: 721
From: Marietta GA
On a past post from a Forum Member, that had similar power issues, the problem turned out to be the main plug on the new harness was not seated completely into the fuse box connection, or possibly where the connector plugs into another harness. You probably would be wise to get a complete wiring schematic that can be found in a Chevrolet Factory Service Manual for a 1972 car. The schematic will indicate were each harness connection is located, and also what devices are on he same circuit. Did you get a new fuse box.
Thread Starter
3rd Gear
Joined: Nov 2021
Posts: 3
Likes: 0
On a past post from a Forum Member, that had similar power issues, the problem turned out to be the main plug on the new harness was not seated completely into the fuse box connection, or possibly where the connector plugs into another harness. You probably would be wise to get a complete wiring schematic that can be found in a Chevrolet Factory Service Manual for a 1972 car. The schematic will indicate were each harness connection is located, and also what devices are on he same circuit. Did you get a new fuse box.
Oh well, the joys of classic cars.
Edit: I do have the wiring diagrams as well, I'll try and trace the whole circuit and see where we start hitting issues. I also read that I think either the TCS or Wiper relay are constant hot, until they get ground I think from somewhere else in the wiper circuit, so maybe a bad ground somewhere is a potential cause?
Last edited by 72C3SB; Nov 21, 2021 at 11:26 PM. Reason: context
