Vintage Air voltage drop

[jchav62]

Originally Posted by 69 C10 LWB

It sounds like you have a voltage drop or bad ground to the cab. If you still have 14 V at the battery your alternator is probably fine. If you had a voltage drop on the fan wire your fan would be slow but your voltmeter should not drop. It sounds like you may have a bad connection where the main power wire goes into the cab or possibly at the horn relay if you still pull cab power from there. Could also be a bad ground to the cab.

I replaced the original wire from the fuse box to the fan switch with a 10ga wire. That seemed to do the trick. The voltage still drops with the fan on, but no lower 13v with the fan on. Around 12.5 on high. Thanks for all you input...

Stay safe! JC62