alternator power wire melted down!!

[greg@berkeley]

as i was driving home today, i noticed my factory voltage gauge was reading lower than usual. i didn't smell anything burning and i didn't want to look under the hood on the side of the road while it was raining, so i drove a few miles to my family's shed where i usually work on the car.

i popped the hood and found that the power wire to the alternator was completely burned through right where it meets the alternator. i took a pic, but i can't post it right now. nothing else seemed wrong. the alternator fuse wasn't blown, and the alt pulley spun freely one the belt was removed. i parked the car and drove a different car home.

what would cause this to happen? why didn't the fuse blow first? is it possible that the alternator is shot even though it spun freely?

i'll get that pic posted a little later. thanks for any response.

 

[madams74]

I had an alternator that shorted out internally. The post for the main power connection was a dead short to the case on the alternator. Take a voltage meter and set it to continuity and then check between the post and the case. You should not have anything there. Then re-connect your wire if OK. If you want you can just take it to Autozone.

 

[94GTLaserRC]

IF that screw comes loose, and the wire is not FIRMLY tight against the alt, there will be an increasing rapid increase of carbon build up, and the connection will act as though there is an extremely thin gauge wire, which will cause it to FRY.

WHen mine did it a few months back, the back of the alternator had a black shooting char mark on it, and it smelled really bad (burnt). Your alternator may still be ok.

I used this as an excuse to buy the chromer!!

GOOD LUCK
RC

 

[greg@berkeley]

thanks guys. the nut over the wire connector piece was too tight to come off. i think it may have melted to the stud. i'll head over to the shed (15 minute drive) after the twins game and take the multimeter to it.

rc, no chrome alternator for me if i need to replace mine. i can't see myself stopping at one chrome piece, and i would rather spend my car money on other stuff! i hear chrome can be an addiction!

anyone else?

 

[greg@berkeley]

i finally got the pic uploaded.

i brought the alternator into hedahl's (auto parts store) today and it tested fine. i guess i just need to replace the power wire. the parts guy at a local ford shop told me i'd have to bring the car into the service department to get it replaced. just another jackass ford employee. he said he couldn't find the wire on the computer and insisted that it was part of the main harness, which it is not. it goes to a post on the fuse box directly connected to the positive battery terminal.

anyway, for those of you who have replaced this wire, where did you get the replacement? did you just buy some 8 gauge wire and hook it up, or did you find a "replacement part" at ford/some other auto parts store?

thanks.

 

[94GTLaserRC]

You can just use the proper length/gauge wire from Walmart....a wire's a wire.

My chrome one was supplied with a 4GA wire per their recommendation, since it is a 160A unit. I used a Walmar one from the fuse box to the battery.
RC

 

[madams74]

The wire has to be the sane gauge abd you need the fusible links that are installed inline with the wire. These are availible at parts stores. The Mustangs came with 2 links that are side by side. You may be able to just get some slack in the wire, and use a new connector. I would just cut the insulation and get about 1/2in of the bare copper showing. Then take a new end and solder the new terminal onto the old wire. The best way is to use a propane torch and some flux cored solder. This is going to have to be done anyway. The do sell a pre made wire and most parts stores that have the ring terminal ends on both sides. You will not have the fusible links on there though. Your call.

 

[greg@berkeley]

madams74, what size are the fusible links? i definetely want to replace them. anything else i need to know before i buy a some wire and two fusible links?

thanks!

 

[madams74]

Well I just used the ones that were labeled FORD. The were in the area at Autozone by the fuses. The ones labeled Ford had the ring terminal end already crimped on it for the side that goes to the fuse box. The other side had a butt splice connector that you are supposed to crimp onto the new wire. Cut the butt splices off and then solder the two ends on the fusible links together against the one wire to the alternator. I had no specs on the OEM links amps so I just assumed that 2 wont hurt anything.

 

[greg@berkeley]

thanks again. are the fusible links right next to the alternator the only ones in the wire? i neglected to test the continuity between opposite ends of the wire...