Altenator problem?

buddha · 04-14-2001, 09:11 PM

Ok, this is a tough one guys. I've put a new alt in the car, as I knew it wasn't charging the battery. It never turned on the ALT light on the dash, but if I disconnected the battery, the car would die. The new alt hasn't fixed the problem.

I've tested the output of the alt and it shows nothing. I've checked all of the wiring and it shows OK on the Ohm meter.

Anyway, I've checked, and rechecked and can't fiqure it out. I don't know what else to look for. As I stated, it never turned on the idiot light on the dash, so it really has me stumped. Anyone have any ideas?

04-15-2001, 02:25 AM

My car did the exact same thing. It turned out that there's a power wire from the ignition switch that turns on the voltage regulator that was grounded and so as a result the alternator wasn't charging the battery and the car was running on the battery, it broke down several times, and it ruined a battery, not only that, but it made me really angry because it was one of about a thousand problems with my car. I never got any lights on in my dash either and when i disconnected the battery it would die. The coil can run with as little as 6-8 volts, so you can have a battery low enough to not start the car, but be able to drive after it's started. Have you checked the voltage regulator to see if it's getting power or if the voltage regulator has any open circuits? I don't know if your stang would have an external regulator because i don't know what year it is and what the later years have, but if it has an external regulator that may be it.

------------------
'84 Mustang 5.0 T5, FMS aluminum radiator & 180* t-stat, 1 5/8 shortys/2.5" duals, '88 GT tail lights and wheels, Holley 4160 4 BBL, FMS smog pump idler

buddha · 04-15-2001, 10:09 AM

This sounds like a possiblility with my car. BTW, it's an 89. I had a buddy help me with it after I was running out of options, and he seems to think theirs a problem with the VR also. I'm going to get a Chiltons today hopefully and check out the schematics. Thanks for the reply....it gives me more ideas.

04-14-2001, 09:11 PM	#1
buddha Registered Member Join Date: Feb 2000 Location: Washington, MO Posts: 327	Altenator problem? Ok, this is a tough one guys. I've put a new alt in the car, as I knew it wasn't charging the battery. It never turned on the ALT light on the dash, but if I disconnected the battery, the car would die. The new alt hasn't fixed the problem. I've tested the output of the alt and it shows nothing. I've checked all of the wiring and it shows OK on the Ohm meter. Anyway, I've checked, and rechecked and can't fiqure it out. I don't know what else to look for. As I stated, it never turned on the idiot light on the dash, so it really has me stumped. Anyone have any ideas?

04-15-2001, 02:25 AM	#2
84stangLX Guest Posts: n/a	My car did the exact same thing. It turned out that there's a power wire from the ignition switch that turns on the voltage regulator that was grounded and so as a result the alternator wasn't charging the battery and the car was running on the battery, it broke down several times, and it ruined a battery, not only that, but it made me really angry because it was one of about a thousand problems with my car. I never got any lights on in my dash either and when i disconnected the battery it would die. The coil can run with as little as 6-8 volts, so you can have a battery low enough to not start the car, but be able to drive after it's started. Have you checked the voltage regulator to see if it's getting power or if the voltage regulator has any open circuits? I don't know if your stang would have an external regulator because i don't know what year it is and what the later years have, but if it has an external regulator that may be it. ------------------ '84 Mustang 5.0 T5, FMS aluminum radiator & 180* t-stat, 1 5/8 shortys/2.5" duals, '88 GT tail lights and wheels, Holley 4160 4 BBL, FMS smog pump idler

04-15-2001, 10:09 AM	#3
buddha Registered Member Join Date: Feb 2000 Location: Washington, MO Posts: 327	This sounds like a possiblility with my car. BTW, it's an 89. I had a buddy help me with it after I was running out of options, and he seems to think theirs a problem with the VR also. I'm going to get a Chiltons today hopefully and check out the schematics. Thanks for the reply....it gives me more ideas.