electrical problem?

steelie4u

Member
Jun 27, 2009
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I had my car sitting for a month or so, went to drive it today and when i got home the battery was dead? the car ran fine no flickering lights, turn signals worked and lights were working never dimming? could my alt be causeing this? if i start the car and remove the negative battery cable will the car still run if the alternator is good?....thxs, is there a better way to test the alternator? it never had this problem before, tonight was the first time i drove it at night with the headlights in quite a while.
 
Don't disconnect the neg battery cable while the car is running on any car with electronics (i.e., your EFI Mustang).

What happened when you got home? Did it not restart? Would the lights still illuminate? Because you noticed nothing abnormal till you went to restart it, it could just be a bad connection.

Parts stores can bench test your alt and battery if needed.
 
Don't disconnect the neg battery cable while the car is running on any car with electronics (i.e., your EFI Mustang).

What happened when you got home? Did it not restart? Would the lights still illuminate? Because you noticed nothing abnormal till you went to restart it, it could just be a bad connection.

Parts stores can bench test your alt and battery if needed.

yes it just wouldnt start when i got home , am going to take the alt today for a check up at autozone, my alt warning light never came on? doesnt come on when i turn key on either? maybe bulb is burned out.
 
Please be more specific when posting. Phrases like "would not start" indicate that it was cranking over but not catching.

You didn't answer if the lights were coming on when it would not crank. If not, it's probably a battery connection issue, not a hard-part failure.

The battery light not proving out is disconcerting. There's a resistor in the circuit to mimic a bulb (the excite wiring goes through that light and to the regulator). I would replace the bulb. When testing that wire at the regulator (labeled I on your reg), it should show 2-12 V.
 
the car cranks but not enuff to start it, its very slow, lights still work, am in the process of testing the alt, charged battery and did wire checks on the d connector and have 12 volts, the stud with power wire has 12 volts, starting to think its the alternator
 
You'll know soon enough. Once you charge the battery enough to start it, check your alternator output. It should never be below 13.0V. If you're seeing 13-15 volts, the alt is charging.
 
had alternator checked and i did voltage check on all connections to the alternator, turned out being a bad 500ohm resisitor in the cluster, replaced it now all is good.............