There is one very quick and dirty test for your fans, remove the connector from the blue two pin connector on the thermostat housing - the fans should run full speed (this is dependant on the fuse, relay and wire being good).

The two relays that run the fans are in the fuse box near the master cylinder - the one a bit rear to the car and is closed with screws. There should be two relays with fuses on top, one relay is blue with a 15A fuse and one is green with a 30A fuse.

There is also a resistor behind the driver headlight near the A/C reciever drier. That resistor is the for running the fans slow. At full speed the resistor is bypassed.

To test it all you need is a test lamp, start the engine and see if you have full battery power at the "out" leg of the resistor, the bypass is simply a wire from the high speed relay bolted there. - so at full tilt the power is supplied there bypassing the resistor. To test low speed test before the resistor.

tracing it down you should be seeing this same voltage at the 2 pin connector which is nested in a spring steel housing next to the radiator. The ground for this is on the ABS pump bracket - its usually ok unless you live in a salty winter state.

In my car the resistor had toasted both hi and low speed wires rendering me with no electric cooling fans, the resistor is available from this site's store and is quite easy to swap out (remove headlamp to get it to it rather than from the top)

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)