Mustang troubles, electrical and shifter/ignition

Hello all,

I’m from New Salem, North Dakota, home of the world’s largest holstein cow. I’m attending college at the University of North Dakota and have a very tight budget. I do know a good deal about cars and how they work however, I have a 1995 ford mustang with a 3.8 v6, and have recently discovered an electricalproblem. First I thought it was just the headlight switch. We replaced it, but looking at the old one, we found that it had gotten so hot, it melted all the plastic off the wires, and that this caused the switch to burn out. I replaced the old one with a new one but it still gets super hot. I’m afraid to drive my car at night for the reason that my lights might fail me in the dark. Another problem, I’m unsure if they are associated, but it did appear around the same time I replaced the headlight switch. When my car is running, it is impossible to shift it from park. The button on the shifter (its an automatic transmission) refuses to give, and the result is that my car can only be shifted into gear by turning the key to turn on the ignition position while pressing in the button on the shifter, and then starting my car and driving off. Another thing that i’m sure is associated with this problem is that the cruise control will not be turned off by the brake. It will disengage the cruise when braking, but reengages after my foot leaves the brake. These last two problems began at the same time. If anyone has any insight to this problem I’d love to hear about it, as I’m tight on funds, and need to fix these problems.

For the first problem, it’s possible you have a bad voltage regulator. It’s also possible there’s a short in the headlight circuit. Or that you (or whoever had the car before you) installed illegal high-output bulbs which are drawing more wattage than the circuit is designed for.

For the second - do your brake lights work? This sounds like your brake pedal switch is bad. This would cause your shift interlock to not release, as it can’t see that you’re stepping on the brake. Same with the cruise control. Easy fix and a fairly cheap part.

The alternator may be generating excessive AC ripple voltage. To see if that is the case remove the connection on the back side of the alternator and then start the car. If the shifter then works and the CC works ok replace the alternator. There are bad diodes inside it. That would also cause the light switch problem due to excessive voltage, even though the DC voltage level may be okay.