try powering the fan directly with a 40 amp fuse connecting the power and fan motor. if the fuse doesn't pop it can't be the fan motor.

 

Exactly... you are prolly running the fan with a larger wire and no fuse. if you want to test this way, you MUST use the same size wire and fuse, and having the same number of connections/contacts would be even better. Total resistance is based all ALL these factors. Even moving up 1 guage size or removing one connection could result in a .25-.5 amp drop and not pop the fuse.

 

I'll try that. Thanks!

 

When I replaced the 40 amp fuse in the car it didn't fail until an hour or two later. I'm guessing the same would happen if I powered the fan directly with the same fuse. So would this test still be likely to give me the answers I'm looking for?

 

It should...

Do you have access to an amp meter? That would tell you for sure what your amp draw is.

 

if you have an amp clamp for your dvom, use that. Otherwise wire the dvom in series with the circuit. Just make sure you have a dvom that can handle at least 50 amps or so as not to melt it!