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Help: No Power to any fuse, but still starts/runs on '79
I picked up another C3 Sunday -- a '79 automatic that starts and runs, but gets no power to anything else -- no power to fuses -- (no lights, no gauges, no radio, no heater.)
I replaced the ignition switch thinking it was the culprit, but still the same thing. I'm crosseyed, so am taking a break before again looking at the wiring diagram. (Of course, I'm looking at the one for my '70, so some differences.)
Any ideas? Could a blow-out of just one fusible link near the starter cause this?
Starter solenoid extension cable? (Not familiar with that piece, other than just hooking leads to the starter/solenoid.) That would cause it to start and run, but not pass along power to the fuse block?
Thanks for the link to the wiring diagrams.
Originally Posted by Bikespace
Well, start with the correct wiring diagram for a 79.
Starter solenoid extension cable? (Not familiar with that piece, other than just hooking leads to the starter/solenoid.) That would cause it to start and run, but not pass along power to the fuse block?
Thanks for the link to the wiring diagrams.
I meant to say "harness", not cable.
Anyway, there are two fusable links that can fail. You could still get it to start, and once running, the alternator could possibly power the HEI. Or who knows. It sounds like you have a lot of work to do with a multimeter.
It sounds like you have a lot of work to do with a multimeter.
Story of my life!
This is payback for buying a really, really inexpensive '79 thinking it would be easy to fix after successfully reinstalling everything in the 1970 interior and fixing lights, horn, windshield wipers. #slapdownforoverconfidence
Story of my life!
This is payback for buying a really, really inexpensive '79 thinking it would be easy to fix after successfully reinstalling everything in the 1970 interior and fixing lights, horn, windshield wipers. #slapdownforoverconfidence
Not judging! My 80 was a complete mess when I bought her, but she started, ran, and drove two hours to get home. My 79 was/is much nicer, but they both need work. As for things breaking, I haven't yet found a correlation between purchase price and reliability. Maybe I will after I finish replacing everything.
I replaced the starter solenoid extension harness in my 80. Both fusable links were melted to bare copper, but still carried current.
Looking at the wiring diagram, I don't see how the HEI could be powered without at least some power in the fuse panel. But who knows. Perhaps the PO bypassed it all with a relay run off the battery.
This one is white/red interior and really a rough POS -- paint is peeling, interior is thrashed. I just love saving cars that are forgotten...getting them to a running/driving.
Come to think of it, the guy I bought it from said that he couldn't get it to start with the key and played around with it. I guessed he just fiddled with corroded wires, but maybe he ran a separate link!?!?
Update: I checked for 12V at the starter solenoid extension harness. I have 12V on the 2 reds and white/red. Black holds ground. I suppose the next step is to check the alternator/regulator thermofuse line. Trying to figure out easiest way of testing that one, but I suppose I'll have to disconnect the bulkhead connector? Won't have chance to look at it for a while.
And the fusable links at the solenoid aren't visibly melted? That's good news. You should have 12V at the alternator with the battery connected. Either way, the problem may be in your bulkhead connector. Or a missing ground...
When you were measuring for 12V on the fuse panel, what were you using for a ground reference? It is always worth checking the battery connections, the battery ground to the chassis (underneath the car), and running a wire back to the negative terminal of the battery when using your multimeter. I'm fortunate enough not to have widespread ground issues in either car, but there are lots of threads showing how to debug them.
White on red is the best color for a C3. I looked for a 79 much like yours to match my wife's black 79. I'm glad you will be able to save another car. It looks like you are well set up to handle anything else that needs fixing!
I was able to confirm continuity with no or minimal resistance from all of the solenoid harness connectors to the harness-side of the bulkhead connector today as well as the alternator wires to harness side of bulkhead connector. My pix below of where each wire connected to the harness side of the connector. Trying to make sure that a previous owner didn't use an incorrect harness/connector.
The bulkhead connector was really nasty/gummy inside. I doused and soaking both the harness and bulkhead side connectors in Deoxit. A couple of the connector pins were also a wee bit bent. It is always a possibility that there simply wasn't connectivity.
The car came with a new headlight switch, but I cannot get the center retaining nut loose to remove the old one. Nothing on this car is easy!
If it were easy everyone would do it. That said there's a main power connector about 6 ta 8 inches away from the bulkhead connector, below the master cylinder. Mine melted a couple years ago. Car ran, power to alternator and HEI. But nothing else. I cut it out, soldered all the wires. All good.
If it were easy everyone would do it. That said there's a main power connector about 6 ta 8 inches away from the bulkhead connector, below the master cylinder. Mine melted a couple years ago. Car ran, power to alternator and HEI. But nothing else. I cut it out, soldered all the wires. All good.
How do I recognize this main power connector, because I do not see it? Are you referring to something mounted on the fender below the master cyl? 6-8 inches from the bulkhead connector under the MC is the cruise control in my car. All of the wires from the bulkhead connector come into a harness and go straight through to their termination points...
Making progress!!! I now have 12V to both alternator red wires and the fusebox. It must have been a combo of bent tabs and REALLY gunked-up bulkhead connector. Now I am finding 12V on one side of fuses and nothing on the other, and finding some really melted fuses. I will clean up the fusebox and press on from there. (Shocking -- bad electrical connections causing heat and melting plastic-body fuses? )
Never found the connector you referenced, 4-Vettes, other than the T in the harness where the alternator wires come out.
03-19-2020, 06:26 PM
Help: No Power to any fuse, but still starts/runs on '79
