90sc charging question

90blackbird

Registered User
My 90 is in the shop. Alternator is charging, but car will only run off battery. Can anyone point me in the right direction. Is there a relay. Car will run until battery is drained.
 
90blackbird said:
My 90 is in the shop. Alternator is charging, but car will only run off battery. Can anyone point me in the right direction. Is there a relay. Car will run until battery is drained.


If your car is in the shop can you have the shop owners take a look at it? How are you sure that your alternator is charging, did you have it tested at an auto store or such?
 
90coug said:
If your car is in the shop can you have the shop owners take a look at it? How are you sure that your alternator is charging, did you have it tested at an auto store or such?
Alternator was tested at shop. It is putting out required voltage. Thought we had it fixed. Drove it about 40-50 miles with fresh battery, died on the road. Put in rechargred battery and drove it home. The machine shows alternator is charging. Is there a relay somewhere else in the car that would keep it from seeing the alternator?
 
90blackbird said:
My 90 is in the shop. Alternator is charging, but car will only run off battery. Can anyone point me in the right direction. Is there a relay. Car will run until battery is drained.
Anyone got any suggestions for this problem. Still can't locate source. Lincoln Mercury Parts guys says he thinks there is a external relay that protects from overcharging of the system. Doesn't know where it is.
 
There are some fusable links for the alternator to the starter relay. Maybe they are bad. Hope this helps.

Shane
 
quick35th said:
There are some fusable links for the alternator to the starter relay. Maybe they are bad. Hope this helps.

Shane
We think we found one, courtesy of a guy at licoln merc that used to be a tech for the Sc'. Will no in the morning if it fixed it. thanks for the response
 
I have a 91 5.0 which I swapped-out the alt for a 200amp.(Thank U Lonnie)

The factory harness from the alt to the batt in our cars is garbage IMO.

I ran my own 4-guage wire+150 amp fuse along with the exhisting wiring when I did the alt swap.
I am thinking of running another wire like that in my SC for giggles...
Can't Hurt!
good luck!
Happy Merry!

paul;)
 
There is a

There is a high current fuse that is in the fuse box in the engine compartment. The wire that goes from the alternator (large back terminal on alternator)....check it for continunity and make sure it has a good connection to the starting relay.

Good luck,

Don
 
90blackbird said:
Alternator was tested at shop. It is putting out required voltage. Thought we had it fixed. Drove it about 40-50 miles with fresh battery, died on the road. Put in rechargred battery and drove it home. The machine shows alternator is charging. Is there a relay somewhere else in the car that would keep it from seeing the alternator?
No.. if the battery is good, the alternator wires directly into it. It is impossible for the car to be running off the battery if you are getting 14 V across the battery terminals. You can check with a voltmeter. It is quite possible that you have a bad alternator, especially if you have a rebuilt one. They can be fragile. For example, the alt can output power at idle and turn off completely after warming up.. your battery will drain itself.

Beg, buy, borrow a voltmeter, hook it into the cigarette lighter and watch it while driving around. 14V, 13.75 at the least, while running. :)
 
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