Help!!! 2nd alternator....

[SHOstuff]

I went and got a new alternator and they tolde me that the reason that the main wire is getting hot is because the alternator wasn't shutting off. It would go up to 15amps when it should be less than that. But that's whats causing the main wire to get hot. If need be, how would I change that wire? Will I have to get a whole new wiring harness?

 

[sdpatt]

I have been through eight replacements of the O'Reilly's brand Ultima alternator for my '91 SHO. Some have lasted less than a week, others as long as 5 years. Unfortunately I have gotten quite good at replacing it through all the practice. The lifetime warranty has kept me from spending new cash on another brand. The last one was remanufactured in the good 'ol USA. I actually believe this one is going to last a while.

 

[SHOstuff]

I have been through eight replacements of the O'Reilly's brand Ultima alternator for my '91 SHO. Some have lasted less than a week, others as long as 5 years. Unfortunately I have gotten quite good at replacing it through all the practice. The lifetime warranty has kept me from spending new cash on another brand. The last one was remanufactured in the good 'ol USA. I actually believe this one is going to last a while.

:laugh_ti: But didn't those bad alternators screw up your wire? Not the plug in but the one that screws on the side.

 

[SHOstuff]

I'm really worried about that wire. What do I do should the next alternator burn that one up by staying on. Someone please help me on that question.

 

[sperold]

If you have cleaned up the wire you are talking about and it seems full size and doesn't have any issues like the connector connections (ie wont pull out when tugged), then you have done enough.

You can better ground your system as people have indicated, but that is up to you as a further enhancement.

Your alternator that you tested and took back had a voltage regulator problem, as it was overcharging and it should have turned you alternator light on while it was at 15 or higher.
The voltage regulator is an electronic part and has a "high infant mortality" situation, where if it is going to fail, it will do it fairly soon after the install.

The whole alternator gets quite hot when in service, if you need proof, try to remove one right after it has been running.... I will guarantee you will have to wait for the cool down period.

 

[SHOstuff]

Thanks Sperold for that. I have a shop service manual and I looked for a fuse for the alternator but there isn't one. Am I missing something?

 

[sperold]

You are not missing anything.
There are fuseable links on some of your main harness routes (aside from the fuses in the engine compartment and drivers dash area), but they are either OK or melted, nothing in between.
You have an alternator issue only.

 

[SHOstuff]

Ok. Great to know! Thank you Sperold and everybody else that contributed to helping me!

 

[sdpatt]

:laugh_ti: But didn't those bad alternators screw up your wire? Not the plug in but the one that screws on the side.

The lugged wire that is secured by the 10mm nut on the draiver side of the alternator is the 12V battery feed and is hot until you disconnect the negative battery terminal. The removlal of the battery terminal is the first step in the replacement of the alternator for a very good reason. I have not had any damage to this wire in 421,500 miles, only the age and heat related embrittlement of the rubber boot that covers it.

 

[SHOtimer]

Everytime I drive my SHO I wonder how much longer my alternator has. The one that Ford installed at the factory 15 years ago is still going strong with 235,468 miles on it.

Doug

 

[Devin]

I just had my second Reman die. I'm done with the Mexican remanned.