Farmall Cub

On the 340ih, I think the 7 year old 12 volt alternator went kapuutz worked flawless until now. I have double checked and cleaned all connections, checked battery 12.35v engine off, and 12.36 running. amp reads -draw

I have a idiot light wired in (diode) and it now stays bright red all The time with engine running at all rpm/s , usually when I rev engine to 800 rpm's the light will go out,,as alternator '' excites" and works as it should. Is there a way I can test the alternator,or should I bring it in for a bench test. any other things I can try,let me know. thanks guys,Jim

Sounds like the alternator has failed. Remove it and have it bench tested if you want to confirm that. All the indications you have listed are of a non-functioning alternator. Probably the most common alternator failure is the internal diodes.

Thanks BD. I will do just that.

Went to local napa dealer, checked my alternator,it ested good, putting out 15 + amps, he cleaned the external connections for me, and sent me home, to double check wiring, clean all connections...they all looked good, I checked alternator mounts, and cleaned the surface of the mounts, to make good ground, installed alternaor and everything was fine again. Must have been a combination of dirty connections and bad ground ...who knows, it works, and all is fine ! thanks,Jim

Sure beats buying a replacement!

very true.