Draano

Hi,

Son's 1989 GT 5.0 manual. Replaced battery in May. Son is out of town in college. Three weeks ago, I went out to start the car to run it around the block and the car wouldn't start. The dome light didn't even come on. I put a trickle charger on it for 24 hours, and tried again. This time, the dome light came on dimly, all the idiot lights came on, but the car wouldn't crank. I checked the voltage on the battery and found it to be at 9.3 volts. I attempted to jump it, but also the same result. Last weekend, I pulled the battery out of the car and charged it in the garage, in the off-chance that there's some kind of a drain in the car (stuck glove box light or a short somewhere). Starting voltage was 8.3, and after charging, it was only up to 9.6 volts. I pulled a battery out of another v8 car in the fleet and attempted to start the car using that one. Prior to hooking it up, I checked the voltage and found that battery to be at nearly 12 volts. The car behaved as it had with the other battery after it had been trickle-charged - Dome light on, idiot lights on, but no crank-age.

What should I check next?

Thanks in advance,
Mike
Wall, NJ

80'smusclecarfan

Well a 12v battery just sittin there (not) under load should be at least 12volts.Barring that,the starter may be stuck,ignition coil/solenoid goes on these routinely and some 5.0's the clutch pedal has to be pressed hard fully to the floor for the car to turn over.I'd check these first then I'm at a loss too. Oh can you hear the fuel pump whine when you turn the key.

forcefeed

ok for starters battery voltage needs to be at least 12.6, if its not get one that is. next step open hood, locate starter solenoid on the fender apron, their are 3 terminal, pull the small wire off the solenoid and have an assistant try and crank the car( does the test light glow), if so the starter solenoid is getting a signal, next make sure the car is in neutral flip the key on again, use a screw driver and jump the large terminal on that same solenoid (should be the one coming from the positive battery)to the other large terminal if it cranks you know there is a problem with the solenoid, if it doesn't than move to the starter, again with a volunteer gain access to the starter try giving it a whack with a hammer while trying to crank it..........let us know how it works out

Draano

Thanks for the replies.

I replaced the solenoid and used a battery out of another vehicle, and it fired right up! I returned the bad battery and got a replacement, as it was completely covered under warranty.

I took a multi-meter to the fuse box and touched the contacts at the top of each fuse. The only one that showed any current draw was the fuse for the dome light, and when I closed the door, the current draw went away.

I'll assume that the battery was bad and the solenoid happened to go at the same time, but will continue to monitor the battery every week or two to see if it's going dead.

Again, thanks! $13 was a whole lot better than having it towed to a garage and paying someone else to diagnose it.

Best,
Mike

Draano

A few days after swapping the solenoid, the battery went dead again. After returing the battery to R&S Straus and getting an exact duplicate, the battery went dead again. I took the car to the local garage, where a very experienced tech couldn't find the problem. He went over the electrical system for quite a while, and finally found what was killing the battery. It was the visor mirror, which didn't show up on his schematic. As it turns out, the hinge on the visor is made of cloth, and had stretched out over time, causing the on/off switch button to remain in the "on" position. He tightened things up a bit, and put something over the switch to cause it to be depressed easier. It wasn't visible, even at night, because the closed visor hid the light from view.

Two weeks without a dead battery, despite sub-freezing temps.

Best,
Mike