When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
1997 F150 - 4.6L
I bought a brand-new alternator from NAPA for ~$220 - not a reman, plus a new belt. I didn't think there was a problem with it for the first week or 2 because I was just driving short errands around town, close to home. Then the other day I went about 70 miles from home and noticed the battery light on and the gauge was all the way up to 18 volts. I pulled over and the alternator was real hot and the water in the battery was starting to bubble a little. I didn't want to over-charge the battery so the only way I could get home is to pull over every 10 minutes or so and run the fan and lights on with the key on and the engine off to run down the battery some and then it would seem normal for a while longer. So before I take the alternator off again and take it down to the store I bought it from to have it tested, is there anything else that could be causing it to overcharge other than the internal regulator? I have a code reader and it doesn't show anything.
You have a brand new defective alternator, go swap it out. And have your new one tested before you leave the store. Remember these "new" alternators are just clones made in china and not OEM equivalent.
The regulator on the unit is faulty.
Always check the system performance when doing these repairs to catch it before is damages the battery, burn head lights out etc.
Of course if it happens some time afterwards, that the chance we all take.
Good luck.
After riding my bike down to the NAPA store with the alternator strapped to my back, they put it on the tester and said it was fine. I have a wiring diagram I'm going to look at...
I read somewhere there's a temp sensor for the battery. If the battery's cold the alt. will charge more. If the sensor's bad it will overcharge. I found this...
Yes the connector has to be locked down.
I assumed you made sure of this.
In the schematic there is no temperature sensing shown.
Any temperature compensation would be done in the regulator by altering the refencing circuit with a tempesture sensitive variable resistance.
Good luck.
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
