Recently my truck alternator has been acting up. Sometimes at idle I am only getting 11.5V. Somedays at freeway speeds I get 12-12.5 others I get up to 13.9. My batts are 11 months old. I stopped at the parts store and they tested the alt for me tonight and the tested indicated a failed diode. I am assuming I have to replace the whole thing, is that correct? Can anyone tell me where to buy the OEM alt for the best price. Should I stick with the stock 110 amp or step up to a larger OEM alternator? In the truck I run a scangauge, A pillar pod of three guages, P3 brake controller, in dash navi system, and I have the factory inverter setup that comes on many newer Ford vehicles.

Thank You

 

The best place to get it was partsguyed.com but he is out sick.

Check the price from there, and then go get a Ford OEM alternator that is the identical PN for you truck -- not an also fit.

You save a few bucks with a Ford reman, but it is worth it.

Do not get a car grade alternator.