problem with alternator wiring on 1993 Ford Sho

I think a wire came loose or the altenator may not be wired right. It is discharging my battery. Need a diagram or a good instructions on how to wir it correctly. thanx

Reply to
fcherylw
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You dont say what happened to make you think that... it's always good to know. And that you think it is 'miswired' sounds fishy..

Here's the thing... the BIG wire goes to the BIG contact and the BIG wire leads through one or two terminals to the battery positive post. It doesnt go THROUGH any relays or switches.

If the BIG wire to the big contact on Alt makes a spark, (or lights a test lite connected between them) when connecting them, engine not running, you have a bad alternator.

Whether the other connector on alt is in place, or not.

Reply to
Backyard Mechanic

Assuming, of course, that it really is discharging your battery, not simply NOT CHARGING your battery.

Reply to
Backyard Mechanic

Reply to
terrorizer3

car dies alternator is not charging

Reply to
terrorizer3

VERY BAD IDEA. DO NOT TRY THIS. On some modern cars disconnecting the battery with the car running will cause the alternator to go to full field and pump 50 Volts or more through the system, which will toast all the electronics to a crispy golden brown.

Yours might not, but do you really want to risk it? If it wrecks the Computer or burns up the main wiring harness, it's scrapyard time

- it can easily do damage severe enough that it would cost more to fix than the car is worth.

People get away with this dumb trick on their car, then they think they can do it to anyone's, which is a recipe for total disaster.

If you want to see if the alternator is charging, get a good digital voltmeter and watch the voltage at the battery terminals. With the car running at a high idle (above 2000 RPM) you should see between

13.5 and 14.5 volts at the battery - 15 volts max, and only if it is very hot outside.

If the battery is at 12.5 volts or lower, the alternator is not working. The bad alternator is not "discharging" the battery, the electrical loads needed to make the car run are responsible for that. Engine Management Computer, fuel injection, ignition system, fuel pump, radiator fan(s), starter, dashboard instruments, dome light, radio, daytime running lights...

Takes 20 to 30 amps to keep a modern car running. If the alternator isn't supplying the power for all the accessories and systems, the power needed has to come out of the battery. And you can only do that for so long before the well runs dry.

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Reply to
Bruce L. Bergman

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