I thought the fan gave up so I bought another. I tested the positive wire and I had 12 volts going to it. The new fan won't run either. The old fan was working fine, then suddenly stopped. I tested the new fan on it's own with a 12 volt battery and it works. I thought it was a grounding problem on the car, but the meter is reading 12 volts when the neg is touched to the grounding source. The fan runs off its own relay and fused switch at the switch panel. I'm baffled. Please throw some ideas this way! Thank, Tony A.

If your meter reads 12v when connected to the ground source then the ground source is no good. With a good 12v input and good ground the blower motor will drop 12v across it. That means you should read 12 on the input and 0 on the output, ground. Check the ground.

My bad explanation. The 12 volt sources were checked without probing the fan. It was just a matter of the two bare wires, pos and neg. So when the red lead from the meter probed the pos wire and the black lead checked the ground, I have 12 volts. I would think this is correct. Anyone else have any ideas? Thnks again, Tony A.

I would say that the relay is bad. You can see 12volts on a contact and still not have enough capacity to deliver many amps!

Easy test. Jump around the relay feed circuit (between the input/output terminals on the relay that feed the 12volts to the fan, usually the 30 and 87 terminal) when having this problem. I see alot of cheapo relays used in kits that bite the dust all the time. Use only quality automotive rated relays. If you have a 30 amp relay, these are usually very cheap. MOve up to a 40 or 70 amps Bosche, Potter-Brumfield or Tyco.

Here is a good heavy duty relay from Newark... http://www.newark.com/NewarkWebCommerce/newark/en_US/endecaSearch/partDetail.jsp?SKU=26C0334&N=0 and the max voltage of this relay is wrongly listed ....it's really 12volts nom.

But, your problem could be on the ground side as well limiting current too. So, plug the fan in.... jump to ground too as a test.