62 Melted Ignition Lead in Engine Harness

[Stephen G.]

I had always noticed that my cars (360 HP FI) brown ignition lead had been taped up with brown electrical tape. This tape job was where the wire terminates at the ballast resistor.

Since the package shelf was out for other maintenance I was able to see the entire engine harness was damaged. I removed the harness from the car to find that the brown lead had melted from the ballast resistor to the ignition switch. In fact I had a hard time removing the connector from the ignition switch. It was somewhat fused on by constant heating.

So the question is what caused it? The ignition switch terminal on the back of the switch was now loose. Did I create that trying to pry the connector off?

The switch was intermittently showing between .2 and 7 ohms between the battery and the ignition terminal. 7 ohms would draw a lot of extra current !

I opened up the ignition switch and found some more than expected contact wear and burning. I've got to get back to garage and test the ballast resistor.

I think the switch caused the melt down. Does anyone else have any ideas?

PS - I think if the FI coil was a problem it would have taken out the ballast resistor before it got the harness.

[Edward J.]

Re: 62 Melted Ignition Lead in Engine Harness

Steve, Alot of times melted wire is a result of a grounded wire, maybe the ing. sheilding touched one of the coil wires, It only takes a moment to melt a harness. since the feed wire from ing.switch is not fused for the ing. system. as is the cigar lighter wire.

[Mike M.]

Re: 62 Melted Ignition Lead in Engine Harness

i agree with ed's evaluation. i also suspect you've created an additional problem at the ignition switch when you pried the plastic away from the spade on the ignition switch(if the spade is now loose on the bakelite .mike

[Wayne M.]

Re: 62 Melted Ignition Lead in Engine Harness

I always thought that cooked insulation on the wiring from the ignition switch to the firewall resistor was a sign that the car was not running but the key was turned to [and left at] ON (run position) for a long time, with the bad luck that the contact points in the distributor were closed; hence constant flow of current through the wire to ground, with resultant overheating.

[Timothy B.]

Re: 62 Melted Ignition Lead in Engine Harness

Wayne,

I think that would burn the points first before overheating the wires..