Fan Controller Failure - MBE ECU?

[ukkid35]

My car overheated recently and I diagnosed fan failure. However I can make both fans run by jumping 87-30 on each relay. The relays are fine, working in all other positions (horn, fuel pump, etc). With the car static I have been testing by unplugging the water temp sensor, the ECU diags show 95.5C - but they don't show either fan on.

What is going on - is the ECU confused/broken?

[ukkid35]

Huge thank you to Aide for both the One-One training session on his superb Android App, and also the MBE loan. Initial tests show that since the fans work with his MBE, it seems that my MBE has indeed developed a fault. There are no signs of damage, no burnt out power transistors in my MBE, so I am still rather puzzled, but very grateful for the opportunity to test with another MBE ECU.

[ukkid35]

spitfire4v8 said:

On remapped chips I only allow fan operation over 400rpm to stop them robbing power from the starter motor on hot starts.

So yes Jools did indeed help me by explaining that the static test won't do it, the engine has to be running.

So everything does seem to work as it should, although it certainly didn't on the way back from Germany.

I am baffled.