Progress Thread Finally got my first Fox Body - 1988 GT

Turn the headlights on and crank the car. If the headlights go out while cranking it's the battery. if they stay on without dimming it's the solenoid on the firewall, or starter. This test works for most cars.

Edit; a loose connection at the battery cables ( either end ) can cause the lights to go off and come back on also.

This will sound crazy to a mustang noob. Hook the battery up leave the key off....car in neutral. Do not do this with car in gear or key on unless you don't like your toes, walls, or the garage door.

Now, with that said....take a screw driver and place it across both big studs on the solenoid on the inner fender. If the starter cranks it's a bad solenoid keeping it from starting with the key. It will spark a little but 12v won't hurt you....its just a little more than a 9v battery.

90sickfox said:

Turn the headlights on and crank the car. If the headlights go out while cranking it's the battery. if they stay on without dimming it's the solenoid on the firewall, or starter. This test works for most cars.

Edit; a loose connection at the battery cables ( either end ) can cause the lights to go off and come back on also.

This will sound crazy to a mustang noob. Hook the battery up leave the key off....car in neutral. Do not do this with car in gear or key on unless you don't like your toes, walls, or the garage door.

Now, with that said....take a screw driver and place it across both big studs on the solenoid on the inner fender. If the starter cranks it's a bad solenoid keeping it from starting with the key. It will spark a little but 12v won't hurt you....its just a little more than a 9v battery.

Click to expand...

He forgot the last and most important part... YOU HAVE TO VIDEO THIS METHOD TO WORK AND POST IT HERE

No.... I'm serious man. It's called jumping the solenoid. The solenoids went bad on all fords. Would give a clicking noise...or sometimes a really slow crank. That thing has 3 studs that are used two big ones with 1/2in nuts and one little one with a red/ blue stripe wire. What happens is when you go to crank the key 12v is sent through the red/blue stripe wire and to the solenoid. The solenoid then sends power from the battery cable to the starter. Jumping the solenoid removes the physical function of the solenoid. The solenoid must also be bolted down tight. The screws that hold it to the car are the ground path.

Don't do like this guy and turn the key on unless you are absolutely sure the car is in neutral and the parking brake is on and works. I know a guy that did this and his mustang started and took a ride by itself down the street, over a curb, and into a tree. This works in all old fords that have a fender apron mounted solenoid.

View: https://youtu.be/ZRlRinL-N-8

DudeStang said:

I figured you were serious but the comment about making sure I film it had me briefly skeptical, lol. Thanks for the detailed explanation though.

So here’s the latest...yesterday, I jumped the fox with my other car. It started up fine and I let it run for a few minutes. Then I turned it off and was able to start it again. Next time I tried to start it, it wouldn’t turn over. So I pulled the battery again, hooked it up to the charger, and let it charge over night. Today I put the battery in and it fired right up. I let it run for a while, then my wife and I took it for a short drive around the neighborhood. After I pulled into the garage, I turned it off and then turned it back on a couple more times. I will probably try again in a little bit to see if it is holding a charge.

Haven’t run any of the other tests suggested yet but will if the battery dies again (assuming that means the vanity mirrors theory was incorrect).

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Have you checked voltage across the battery terminals? Start with checking it now, and then see where you are in the morning. You’ll know if it’s holding steady after getting it charged up.

DudeStang said:

Voltage is varying between 11.xx and 12.xx a little less than two hours since we drove it. Started it again after checking voltage...cranked right up.

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is that positive battery terminal cracked?