I was replacing eyelet on back of alternator. it slipped out of my hand and grounded out against the alternator and i heard a pop. Now my battery light is on and I checked all my fuses and I dont think its the regulator as all my wires were disconnected on my alternator at the time. My mistake was not disconnecting the battery. please tell me its something simple.my brother said i may have fused the relay for the idiot light, meaning nothing is really wrong but the light will stay on. Is this possible?

 

There is no relay for the idiot light, it is controlled directly by the alternator thru the regulator connector (which you had disconnected). What is operating voltage? My guess you fried a diode in the alternator but hopefully I'm wrong and find something more simple.

 

I was hoping it wasnt the alternator. When I turn on the lights and then start it, the lights brighten. Does this mean my alternator is charging the battery? I am sure it is close to the time of replacing the alternator anyways, so maybe I'll do that. Is there a fusible link on that line? I couldnt find one. My voltmeter reads between 28-30 volts. Is this right? I have the black grounded and the red on that bolt on wire.

 

If the truck operates as normal other wise, and the battery light is on, check the alternator field fuse next to the mega fuses.



Depending on the wire you shorted it could be Fuse #19 in the Junction box fuse panel.

If the truck does not operate as normal, I would suspect one of the mega fuses.

This is if you shorted one of the Violet w/ White stripe wires.

 

It runs fine. I'm just waiting for the battery to start dying. I checked all the fuses, they seem good. Thanks for the help, I'll probably have to get an alternator here soon. not sure if my multimeter is accurate,it's a 1981 Sanwa and is really hard to read in the dark.lol

 

Seem good ???

When you put a meter probe to the pins on the back of the fuse, did you have + VDC on both pins ?

A fuse is Either good or bad, nothing subjective about it.

Did you check that one ATM fuse in the Mega fuse block ? It is easy to over look

 

Another way to check that mega fuse is to measure battery voltage right at the alternator B+, the one you had disconnected. It should read the battery voltage, if 0, then that mega fuse is dead. Get a better volt meter, it is alot cheaper than an alternator.

 

Well I fried the diode like you said and the rectifier is screwed, so put a used alternator in, and everything is good now. Thanks for all the help, good to have educated people to offer advice. I have a good digital voltmeter somewhere, just can't find it right now.