QuestionHi, I'm interested in purchasing a beautiful 69 mustang for a great price, but it has two problems, the battery wont hold a charge, and the headlights turn off randomly as you drive. I know it has something to do with electrical, but my knowledge of the electrical components in a 69 is non existent, so I was hoping you could tell me what course of action I should take to find the source of the problem, or if you know whats wrong by what I've just told you, could you let me know what it is? Thanks
AnswerI know that electrical problems seem daunting to someone who is not used to dealing with them, but usually, the solution is pretty simple, and not that hard to identify with a little coaching from the sidelines, which is what I am here for.
On the headlight problem, it is about 90% certain that you have a circuit breaker (it's mounted on the headlight switch) that is failing or is unable to tolerate the load that is being put on it. If someone has changed the headlight bulbs to Halogen bulb without upgrading the circuit breaker, that can do it. If that isn't the case, the breaker has probably just simply died of old age. These are cheap, available at any parts store, and easy to change, once you know how to do it. Again, that's why I'm here (or any of the other volunteers).
On the "won't hold a charge" situation, that usually means something in the car that should go off when the key is turned off isn't going off, and therefore draining the battery when the car is parked. This could be a problem with one of the "always on" circuits in the car - these are the courtesy lights, any trunk or glovebox light, cigarette lighters, power antennas, or power seat motors, or it could be some accessory that someone has changed or added to the car that isn't hooked up right.
There is a procedure for tracking this down, but it requires that you have a multi-meter and some savvy about pulling fuses and tracking down current leakage.
There is also an entirely different scenario for this, and that is a bad battery or alternator, and again, that is a simple problem to troubleshoot but it requires the same test equipment.
If you like the car otherwise, and it hasn't been modified with some strange accessories like a big whopping stereo system or the like, go ahead and buy it- I don't think either of these problems should make you afraid to buy it. Of course these are very good negotiating situations - drive a hard bargain, in case you wind up having to take it to an automotive electrical shop to get it straightened out. I don't think that will happen, but it might.
One thing I will ask you to do if you do buy it is to order the shop manual for the car - we'll need the wiring diagram, and you'll use the shop manual for many other things you will do to it while you own it. These run on eBay all the time.
Good luck.
Dick
