Major Electrical Problem - 75 Vette
Thread Starter
Pro
Joined: Nov 2004
Posts: 659
Likes: 0
From: Flower Mound Texas
Major Electrical Problem - 75 Vette
A buddy of mine made a big mistake.
Actually, that's a lie - it was really me!
I re-installed my driver dash, and connected the battery back up. Everything OK so far. Then I noticed that I forgot to reconnect the hood latch release. This is where I made my mistake - I did not disconnect the battery cable. So as I'm positioning the latch release to align the bolt holes, I moved a couple of wires I guess, heard a small "poof" and then saw smoke coming out from under the dash AND from under the hood at the firewall.
The odd thing is, car started fine that day and all systems checked out ok. Next day, however, I turned the car over once and shut her down. Then when I tried to restart, everything is dead. And I mean dead! I though maybe the battery had fully discharged, so I jumpered it and immediately saw the cables start heating up so I disconnected immediately. I obviously have a dead short to ground.
Any ideas what I burned up and / or pointers where the short could be?
Actually, that's a lie - it was really me!
I re-installed my driver dash, and connected the battery back up. Everything OK so far. Then I noticed that I forgot to reconnect the hood latch release. This is where I made my mistake - I did not disconnect the battery cable. So as I'm positioning the latch release to align the bolt holes, I moved a couple of wires I guess, heard a small "poof" and then saw smoke coming out from under the dash AND from under the hood at the firewall.
The odd thing is, car started fine that day and all systems checked out ok. Next day, however, I turned the car over once and shut her down. Then when I tried to restart, everything is dead. And I mean dead! I though maybe the battery had fully discharged, so I jumpered it and immediately saw the cables start heating up so I disconnected immediately. I obviously have a dead short to ground.
Any ideas what I burned up and / or pointers where the short could be?
Melting Slicks
Joined: May 1999
Posts: 2,897
Likes: 0
From: Moon Township PA
Unless you are a wizard at electrical troubleshooting and splicing, you might consider the easy way and just replace the dash wiring harness. You obviously have a dead short. I know that is the direction I would go.
Gary
Gary
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
I'd guess the place to start would be with the wiring diagram. A smoke incident would hopefully blow a fuse to prevent further damage. Once you let the smoke out of the wires you have to find out exactly where it came from or else you may be vulnerable to the more serious Ball Of Flame incident.
Rick B.
Rick B.
Team Owner
Joined: Aug 2000
Posts: 21,457
Likes: 463
From: Massillon,Ohio USA
2020 C3 of the Year Finalist - Unmodified
Cruise-In VI Veteran
St. Jude Donor '08-'09-'10-'11-'12
I've had my '75's dash down a few times and anyone here that has had a C3 dash down(especially driver's side)know that the way the speedo & tach pods fit on each side of some of the dash holding brackets can CREATE pinch points for the wiring harness. Probably what happened is a hotwire was pinched in between one of these "brackets" which fastens to either the steering column or pedal assembly. I noticed this the first time I had my dash down and carefully & neatly used nylon wire ties to hold it up out of the way just for this this same reason(pinching of the harness).
Thread Starter
Pro
Joined: Nov 2004
Posts: 659
Likes: 0
From: Flower Mound Texas
Good advice. I got the wiring diagram and one problem I found is the starter / solenoid was a dead short to ground. With the battery positive connected to the starter and the wiring harness completely disconnected, the starter was blowing a seven amp in-line fuse that I had put in between the battery post and cable. I removed the starter and had it tested and they told me it was good. I bought another one anyway and installed it, went through a tedious process of connecting the wiring harness without fuses, inserting fuses one-by-one and now everything seems to be okay. But I am still worried about where the smoke came from...
Instructor
Joined: Mar 2004
Posts: 199
Likes: 0
From: mobile alabama
underneath the master cylinder at the firewall wiring harness junction block there is a couple of fusible links , these fuse links kill power to almost all underhood components , my car broke a connector at one of these links and would not start , the smoke you describe sounds like one of those links burned , depending on how bad yours melted into itself you may need a harness after all , if you buy a harness send me some mail i need a single green and black wire from a discarded harness, hope this helps , james
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