Brown white wire melted under dash
 

I'm restoring my 68 GTO to original. I hope to have the car judged some day so I'm trying to keep it looking original. Every square inch of the car has been restored including the wiring. I have all new harnesses from M&H. I have spliced nothing into the harnesses it is as it came from M&H. I have checked the lights the radio tape deck engine spins over and has spark. I had the alternator rebuilt and restored to factory and I put a solid state regulator on the firewall with my original cover. I started the car yesterday for the first time with the body on the frame. It was an awesome feeling to hear her run after all the hours of work. After the engine ran for 30 or 40 seconds I noticed smoke coming from the dash. I shut the car off and pulled the battery cables. I looked under the dash and found the brown wire with a white tracer had melted. I traced the wire from the ignition switch to the wiring block that goes out to the engine. Nothing in the engine area is melted. But I did notice that the alternator got hot almost immediately upon the engine starting. Hotter than I thought it should be after running only 15 or 20 seconds. Any help would be appreciated.

Make sure the proper wires are arranged in the clips, e.g. 2 wires into back of alternator. Mine were reversed on my M&H engine harness. Had to get out the 68 wiring diagram and check all the clips with multi connections after that.

Did that melt your brown white wire or did it make the alternator run hot.

According to the 68 wiring diagram the blue and black white wires that go into the alternator are in the correct position. But if you go completely by the wiring diagram it's confusing. Because the main large black orange wire that is held on to the alternator by the 7/16 nut is on the other side of the alternator in real life. So if I go by the diagram and say the wire closest to the large black and orange wire is the blue wire then my plug is wrong. Here is a picture of my plug and how it sits in the alternator.

New switch? The switch accessory terminal appears to be grounded in the run position..
I'm thinking the ignition switch is defective or mis-wired.

Ok I will look at that tomorrow morning. If I do need to replace the switch who makes a good one that I can use my key tumbler in. Our host says my original tumbler won't work in there switch

I want to start off by thanking those who tried to help me in my frustrated first post. Nothing works than taking your time and then things go wrong. Anyway with my full schedule of auctions and also doing photography for our auctions I finally had time to sort this wire burning issue out. What I found was the brand new headlight switch I bought is shorted out inside. Of course this took forever to find but when I found the issue and replaced the new switch with my original one life got a lot better. Process of elimination with pulling fuses and a test light. Car ran for about 15 minutes and no smoke. I kept checking the resistor wire with a infrared thermometer and also by touch and no issues. Thank you all again thought I would follow up and let everyone know what the problem was.

Jeez, what a pain ... most people usually assume a new switch is good.
Glad you got it sorted.

Even the new "Delco" stuff is made in Trashcanistan these days and should be very suspect.
So glad that you did not melt down all that hard work!

KK68 just wanted to show you how my wiring harness is and everything thing works good. Here's a picture of my alternator plug and my regulator plug. Also if you go by the wiring diagram that's out there for sale I believe it to be wrong on how the regulator wires line up in the connector. In the diagram the blue wire is in the second from the bottom and black / white is in the bottom slot. On my original harness these 2 wires are switched blue on the bottom and black/white is the second one up. On my M&H harness it's the same as my original. Blue is on the bottom b/w is second one up. I believe the diagram to be wrong. Thank you for your help.

This is what I usually use for the 68:


http://forums.maxperformanceinc.com/...1&d=1641314376




But this is from Service Manual:


http://forums.maxperformanceinc.com/...1&d=1641314376




And this is Firebird:


http://forums.maxperformanceinc.com/...1&d=1641314376




And the Big Car:


http://forums.maxperformanceinc.com/...1&d=1641314376




The problem may be that the regulator or wiring was for another model?
(or wired for another model)


The main point would be that the field wire from the regulator should go to the 'F' field connector on the alternator.
(usually blue)


:)

dd:

Yes, I agree that diagram is wrong for voltage reg wires. Here's mine which is the same as yours. However, when I initially did my startup and breakin I was not getting the battery to charge. After switching alternators, voltage regs, etc, discovered that the M&H harness wire clip into back of alternator (R on left, F on right side) had the blue and black wire reversed (see last pic). Fortunately no damage done, switched them around and all good since. Glad you got yours straightened out and found the faulty cause (bad headlight switch). Chasing the electrical gremlins are a big pita!

Am I glad I found this post !
I've got a brand new light switch to . . . I'm gonna check every new component now.

Is it just me ? . . . I'm finding production flaws in al most every new thing you buy.
It's like quality control is a thing of the past or even quality for that matter.

Thanks for the post.

It's just you...The counterfeit Chinese crap at the awesome prices is always sooo superior!
NOT.

Yes I started pulling fuses until the test light between the negative cable and the negitive battery post went out. Then started narrowing it down from there. Once I unplugged the new light switch the test light did not come on. I double checked by plugging light switch back in. Yes new light switch was bad. Plugged my old original switch in and test light did not light up. Started car and held a digital thermometer on the burn wire and no heat.

The switch that was bad was for a hideaway headlight car.

I recently installed a new M&H engine harness in a '65 and two wires that plug into the voltage regulator were reversed so I got voltage to the coil for start but not when I let go of the key. Took 8 hr of tracing and process of elimination including taking the ignition switch out.

I have replaced my 68 GTO engine, a/c and dash harnesses in past three years (Not all at once) and have found M&H to be spot on with all the wiring and color codes.
I recently replaced the original externally regulated Alt with a more modern and higher amp output internally regulated Alt. H&H makes a special harness that allows you to plug the wires to the external regulator so your dash lights will work properly.
The internal reg Alt is an improvement, but I am not completely interested in exact original for these kinds of item. I prefer function over originality.

No it's not just you. I had purchased a new voltage regulator years ago that was bad right out of the box.

I had the same exact problem on my 74 Grandville. In the past year or so I have l had the switch just mentioned, two alternators for my 06 ford truck, two Pertronix flame thrower distributors, and three voltage regulators for my buddies 70 Lemans. Finally got a 50 year old original regulator from a local guy. Car has since been converted to and internally regulated one wire set up.