The alternator in my '89 (302) F150 keeps failing. It is the third time in the 4 years I have had the beast. Has anyone got any idea why it should do this, what to check for, and where to get a replacement that is not likely to do it again???

My F150 is not the best of trucks, but it would be nice if I could use the thing.

Theo

 

Bad ground, bad battery, loose belt, bad wire to the ALT light in the dash, or something about where/how you drive it.

 

Did you also change the wiring harness connection to the alternator.
I went through two in about a year and when I went back for the third one the parts store told me they wouldn't honor my warrenty again unless I changed my wiring harness connection.
Of course this time the replacement altenator actually came with one so I changed it and didn't have anymore problems.

 

Ditto on Stampede. If the harness connections are loose/corroded it will cause heating of the rectifier bridge and eventual diode failure. Buy a replacement that comes with a new harness plug and swap it in.

Randy

 

Thank you, Guys. I will try that, and see if it lasts more than 9 months.

Theo.

 

MY dad and I nick-named that harness system and alternator the "Flame Thrower" we had 3 catch fire in the space of 8 months. Finally the last one fixed the problem. Buy a good HIGH quality alternator not a cheap auto zone POS, pay through the nose and get it at napa, car quest, or the dealership.