I've had an ongoing electrical problem(s) with my car for a while, and decided it's time to try and solve them for good. The car is a '72 Mach 1, 351C, no A/C. Most recently, the car has needed to be boosted, and the lights are running excessively dim. I checked the voltage across the battery while the car was running and got right around 12 V. I then removed the alternator and took it in for testing, where I was told it was working (which is good because it only has about 40 hours of use on it!). So I turned my attention to the wiring, which as you can see, is a mess. I've discovered that a lot of the wiring is in rough shape (exposed wires in some cases). I decided this would be a good place to start.

So, I would like to start with a few questions about the regulator connections. From other posts, I've learned that the connections on the regulator are referred to as I, A, S and F. Here is what I have :

I - connection is amputated
A - This connection has 2 leads, one goes to the regulator condenser (fender mounted) and the other goes to a connector that leads to the solenoid (sorry, I don't know the term for this).
S - This connection has 2 leads, one goes directly to the automatic choke, and the other goes to a plug that connects into the (main?) wiring harness.
F - This is connected to a lead from the FIELD connection on the alternator.

So to start, a few quick questions :

- How can I test the condenser that is attached to the regulator? What would the symptoms be if it was failing?

- What (if anything) should the 'I' lead from the regulator be attached to?


Thanks in advance, if anyone has any related comments I'd love to hear them.

Here is my wiring mess:

 

Sounds like the regulator is not regging. IF the alternator tested good, then I would look at the regulator not telling it to charge. This may help.
http://www.themustangshop.com/resources.cfm

 

Thanks for the link, it's a bit easier to read than the diagram I have.

I also learned (I think) that thing that looks like a condenser is really for noise suppression.

 

Yeah, you need to check the VR. That noise suppressor is a condenser.

 

Correct. Without that you get an annoying hum in the radio that fluctuates with engine RPM.

 

Thanks for the responses. I've completed rebuilding the harness, and as evil suggested, it now looks like I need to check/replace the regulator (hey, the wiring needed to be done anyway :-) ).

Are there any simple regulator checks I can perform myself? I had read a previous post about checking a reading across 2 of the Regulator connections, but I can't find that post again ...

 

I believe that you should find batt voltage on the A teminal with the key on. If you jump that to the F terminal when the car is running, you should see the voltage at your battery climb. Don't jump it for more than a few seconds as it causes the alternator to go full charge. If you see the volts climb, the reg is bad.

 

Just wanted to close the thread out. I saw the behavior that Stepman suggested and subsequent replacement of the regulator got everything working again.

Thanks to everyone who replied.

I'm considering a thread about the crappy dash light intensity on the 71-73 series!! :-)