Dash harness melted

[DarrenX33]

This happen to anyone else? I was driving my 72 on what was likely one of the best days of the summer. Put a ton of miles on the car that day. However, at the end with 1 mile to go to get home I started smelling burning plastic, then saw smoke. I pulled over and shut the car off and the smoke stopped. But when I started the car again it started smoking again. After having the car towed I found this (see pics). Previously I had replaced all the wiring in the engine bay due to the hacked original harness while installing a Chapman lock (a previous owner). Fortunately none of my new wiring burned. But this resistance wire smoked from the fuse box to where it meets at The igniting n switch and is crimped to an orange wire, I believe it's the heater. After tracing I see it runs to the brown wire at the alternator. Taking a look under the dash it looks like there was some hacking done there to, aftermarket stereo and what looks like caps to prevent noise. As I start investigating to find the root cause I find more surprises. Trying to figure out if my ignition switch caused this.

http://img.photobucket.com/albums/v370/darren_costello/1972%20Corvette/091ECC47-6C7E-4EAC-A3C8-1D386CBCBAFF.jpg (http://smg.photobucket.com/user/darren_costello/media/1972%20Corvette/091ECC47-6C7E-4EAC-A3C8-1D386CBCBAFF.jpg.html)

http://img.photobucket.com/albums/v370/darren_costello/1972%20Corvette/639113B4-CBA5-4B83-9BB7-DFAD4DD0ED94.jpg (http://smg.photobucket.com/user/darren_costello/media/1972%20Corvette/639113B4-CBA5-4B83-9BB7-DFAD4DD0ED94.jpg.html)

http://img.photobucket.com/albums/v370/darren_costello/1972%20Corvette/D400FD3E-66AA-4E46-86CA-0A6CABAC7B9D.jpg (http://smg.photobucket.com/user/darren_costello/media/1972%20Corvette/D400FD3E-66AA-4E46-86CA-0A6CABAC7B9D.jpg.html)

Why the splice here off the door plunger?
http://img.photobucket.com/albums/v370/darren_costello/1972%20Corvette/CB45DAAC-E3F5-4826-9668-D9BD1AAE8E2E.jpg (http://smg.photobucket.com/user/darren_costello/media/1972%20Corvette/CB45DAAC-E3F5-4826-9668-D9BD1AAE8E2E.jpg.html)

Cap for noise
http://img.photobucket.com/albums/v370/darren_costello/1972%20Corvette/E9232B68-13C7-42EC-8A85-15C138862057.jpg (http://smg.photobucket.com/user/darren_costello/media/1972%20Corvette/E9232B68-13C7-42EC-8A85-15C138862057.jpg.html)]

I then discover that someone put a 42A alternator on this car which has an aftermarket stereo and AC?
http://img.photobucket.com/albums/v370/darren_costello/1972%20Corvette/1BFD12FE-94B3-4D00-B277-4D37A3822213.jpg (http://smg.photobucket.com/user/darren_costello/media/1972%20Corvette/1BFD12FE-94B3-4D00-B277-4D37A3822213.jpg.html)

[DarrenX33]

Ok. Here it is. Burned al the way through. Crimped with orange @ ignition.

http://img.photobucket.com/albums/v370/darren_costello/1972%20Corvette/A2DFC66F-CDA2-4E9B-B870-2F40A0F0C93E.jpg (http://smg.photobucket.com/user/darren_costello/media/1972%20Corvette/A2DFC66F-CDA2-4E9B-B870-2F40A0F0C93E.jpg.html)

http://img.photobucket.com/albums/v370/darren_costello/1972%20Corvette/56C1E5C9-9E06-4AD7-86D4-B229483149B5.jpg (http://smg.photobucket.com/user/darren_costello/media/1972%20Corvette/56C1E5C9-9E06-4AD7-86D4-B229483149B5.jpg.html)

[Bill Pritchard]

Glad it wasn't any worse, Darren....you've had enough bad luck with that car. Splice at the door plunger is undoubtedly something to do with the alarm. The guys who installed those alarm systems were not exactly electrical engineers <<GRAEMLIN_URL>>/frown.gif

[resto4u]

replace the whole harness and count your blessing that it did not catch fire.

[DarrenX33]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: resto4u</div><div class="ubbcode-body">replace the whole harness and count your blessing that it did not catch fire. </div></div>

That is the end goal. But the last thing I wanna do is go thru all work (not so fun with a vette) and $ to install a new harness only to have that smoke to. I need to find the root cause. Other than melted wires, I've found nothing obvious so far.

[L78racer]

check for cuts / rub-through near your ignition / distributor shielding.

[napa68]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: resto4u</div><div class="ubbcode-body">replace the whole harness and count your blessing that it did not catch fire. </div></div>

X2 Darren. I feel for ya. Electrical in a Corvette can kinda suck!

Tim

[DarrenX33]

Can anyone tell me what the purpose is of the brown and white striped resistance wire on the interior side?

[earntaz]

If it is paired with the orange at the ign sw -- check it thru the body connector to the voltage regulator ... TAZ

[DarrenX33]

According to the diagram. At the ignition switch, the orange wire goes to the heater switch and the brown and white goes into the engine bay to the alternator brown. The alternator has an internal regulator. It's also 42 amps which is wrong for the car. Should be 61.

[earntaz]

So it has an internal regulator? Hmmm -- was it converted? Also, check those damnedable Scotch connector splices -- they can shake loose and cause issues. TAZ

[DarrenX33]

72 Corvettes had the internal regulator. But as i mentioned, my car has the wrong alternator. It is an internal one but it is only 42 amps. It should be a 61 amp because my car has AC, as well as an aftermarket stereo.

[Kurt S]

Close, I have a 73 Vette AC alternator I don't need....

The output of the alternator won't matter, but it sounds like the you need to check out the brown alt wire.