1968 Fuse Issue

[robert campbell]

Steve,
The plug Neil describes is a 4 prong gang style plug. It will unplug both the backup lights and the neutral/park switch.

A test with a volt ohm meter could be done but direct current is funny. Sometimes a switch will work without a load (12 volt power) and will fail when the voltage is applied.

First do what Neil suggested. Unplug that plug. It is on a harness on the firewall aft of the left valve cover. Sometimes hard to see with the firewall brace being a bit in the way. But you should be able to find it. It may take a small sharp screwdriver to pry apart. Be nice to it a clean it out. Always put some lube on it before plugging back together.

So with it unplugged if your use does not pop you are getting closer. The backup lights wiring is part of the rear wiring harness. You can see the pig tails to the backup lights in the trunk wells on each side. sometimes owners love to shove all sorts of "stuff" in those trunk wells and the wire could be damaged in that area.

My guess is the backup/park/neutral switch. The test will isolate the short to this area of the wiring and switches. It is very easy to change out, but the adjustment can be fun. If it gets to that, we can step you through it.

Rob

 

[franklinair]

The square connector. It furnishes power to the Neutral safety switch AND the Backup lights.

Neil

 

[stangfan]

Thanks Neil and Rob.

 

[stangfan]

Turns out the problem is in the wiring between the transmission light and the connector. I figure that with all the movement that happens when you shift from park to drive etc the wiring has possibly chafed against something. I'm going to open it up tomorrow and see what I can find

Thanks for all the advice. :grin:

 

[franklinair]

Steve;
Did you locate the short in the indicator lite circuit?

Neil

 

[stangfan]

I haven't yet. When I first bought the car, I had to replace the bulb. After we discovered that wiring was the problem, I remembered that I wasn't too happy with the condition of that harness. I will get in there and have a look, but I am seriously considering ordering a new wiring harness and just replacing it.

Is it a difficult job to replace it? Does the wiring just go under the carpet to the trans opening?

 

[franklinair]

Console? Non console? NPD sells both types of lights.
Naturally you'll have to gain access to the shifter mechanism.
The wire runs forward, under the carpet to the connector.

Neil

 

[stangfan]

No console. Sounds like it shouldn't be too difficult to replace then. :grin:

 

[stangfan]

We found the short. The power wire (blue with red stripe) has a plastic collar inside the bulb socket which is supposed to isolate it. A tiny bit of that plastic had broken off and slid down the wire, causing a short. We were able to put some electrical tape on the wire in place of the broken bit and it's king perfectly now. I think the heat from the light bulb had made the collar brittle and it had failed.

Good to go! :grin:

 

[franklinair]

Ford junk. Every 40 or 50 years you gotta fix something...:grin:

Neil

 

[stangfan]

Yeah, not too bad when you think of it! :grin: