Keep popping alternator fuses!

[Boostedexcel]

A while back I blew the 80amp alternator fuse, so I replace it and everything is fine. Now, the other night I go to start the car and the battery light comes on. So, I go check the fuse and guess what? yeah, it blown out yet again. So I put another fuse in, connect the battery, get a nice little firework show plus another blown fuse!

Has anybody else had a short this bad or could it be my alternator? I know its somewhere in between the battery and the alternator but not sure what to check. Anybody have an idea?

so nobody has ever blown an alt. fuse??

 

[jastermerrel]

Check for shorts or maybe the alt is bad? I don't know if they can blow a fuse if they go bad, maybe a voltage regulator or something. Get the alternator tested for free at autozone to at least rule it out.

 

[DROOPY209]

Get the alternator tested for free at autozone to at least rule it out.

I don't know if I'd wanna get my alternator checked by auto zone.
Their machines said (6) alternators were good, they were all bad on my car.

The 7th one ended up working fine on my car.

If it says its bad, its bad. If it says its good, you might want to double check and have the alternator bench tested somewhere else as well.

If you keep blowing fuses, and your alternator turns out good, you might want to replace your alternator to fuse power cable with some 4 gauge power wire, and your alternator fuse to battery cable as well.

your stock 10 gauge wire is too thin anyways.

 

[Old Mitsu Tech]

Disconnect your alternator wire and the positive wire off the battery. Hook an ohmmeter between either end and ground. If you have 0 ohms resistance, start looking for something that either got pinched or rubbed a hole in the insulation.

Good Luck

 

[janks85]

check the voltage reg and the connection to the alt it might be grounding to the alt or frame somewhere, i had the same prob but the voltage reg rotted off the alt and grounded to it, which blew the alt fuse

 

[Birt96gst]

just replace your alternator and make sure you have your battery disconnected when you do it. Your alt is most likely shorted out I had the same thing happen to me and a new alternator fixed it

 

[TransAmConvert]

Ok, I had this problem and I'll tell you what caused it for me.

On the Alt, the main power lead connects over a stud and is secured by a nut. Underneath that, there is a plastic spacer/insulator. If this spacer is cracked/smashed/broken/gone, the alt power wire will ground out against the case of the alt and cause what youre describing.

 

[Boostedexcel]

Ok, I had this problem and I'll tell you what caused it for me.

On the Alt, the main power lead connects over a stud and is secured by a nut. Underneath that, there is a plastic spacer/insulator. If this spacer is cracked/smashed/broken/gone, the alt power wire will ground out against the case of the alt and cause what youre describing.

Yeah, I'm thinking this might be the problem. I tried running it without the spacer and it instantly fried the fuse. But I'm pretty sure the car blow a fuse with the spacer in place. The weird thing is I drove my Colt tonight and there was no battery light with the blown fuse still in place.

 

[un4givin68]

do you have a system in it i had the same problem when i put in a 2 farad capicitor in it if so start by un hooking you system piece by piece till it stops then you wil know what is blowing it out after i took the cap out it stopped

 

[2tsi_auto]

I got my car back for sls after they did a motor swap and my fuse keeped popping and thay had a wire on the altanator on the wrong spot. It was a new altanater and had two posts. cheak your altanator. if you took the wires of you might of crossed wrong one like tthay did to mine.

 

[KansasDSM]

If you bought the alternater at auto zone take it back have them test and if it does test out good tell them it is popping fuses and thats why you wanted it checked, then ask them if they can replace it if they tell you no ask to speak to their manager I work there i know how this works they can return it as a customer satisfaction and get you a new one have them test it before you walk out the door too, you might get one that rebuilt wrong or built wrong at parts house, if the manager wont cooperate ask him for his district managers number. it sounds to me like voltage reg went bad or the positive connection crudded out they tend to crack like trans said.