Code P0481 on 99 Century

[4boostin]

I have a service engine code of P0481, which Auto Zone says is: Engine cooling fan primary circuit condition. Possible causes are: Cooling fan relay defective or wiring and connectors.

I made sure both fans are working. Pulled all the relays and fuses related to the cooling circuits. Cleaned and checked for corrosion.

Is there any way to know which relay is bad, because there are two or 3 labeled part of the cooling system?

Any suggestions??

[maxwedge]

Find some wiring diagrams that should outline wiring/ relay info, at autozone.com repair guides, register and go to your car, look for wiring diagrams.

[bozr]

The schematic to test the relay is marked on the side of it.

For the 5 prong 3602 relay (double pole);
There is continuity between 30 and 87a

When 12 volts is applied to 85 and 86 (the coil) there is continuity between 30 and 87


For the 4 prong 3604 relay (single pole)
When 12 volts is applied to 85 and 86 (the coil) there is continuity between 30 and 87

http://www.eurekaboy.com/f250/relay101.htm

[4boostin]

OK, I'm still trying to chase down this problem. All the relays are good. It's been narrowed down to be the computer or the wiring from the computer to the relays. Anyone ever seen this problem and or have any suggestions?

[4boostin]

The wiring harness that goes above the battery was laying on the end of the battery. Acid got into the wiring and corroded a wire.