Air Con Pusher fan Not Turning

[kanewesley]

Wpoll...What a clear concise explanation of what should do what !!!

It's been as clear as mud up to now !

I did watch a youtube vid of a guy activating his auxillary fan on an E46. When he clicked on the E-Blower ON button he got a small window up which allowed him to input a percentage of what he wanted to run the fan at. Obviously not with the E53 !!

When I select E-Blower ON...I get nothing. but this may not mean the fan is buggered....it may be that the square wave signal is absent.
Thats why I need to prove this before I buy a new fan. signal...or fan.

There is 12v at the fan so the power is there but I still don't know if the sq. wave signal is there to ramp it up.
I was hoping this may be monitored in INPA.

I'm presently looking for a small hand held oscilloscope on Fleabay to try and take this investigation further.

Finally, yes, the aircon does work when the car is moving forward but I dare not leave it running when in standing traffic because thats where this whole saga began last year....it just didn't stop blowing cold....because there was no cooling of the system, the pressure build up ws so great it blew the compressor and I dont want that to happen again...I would sooner get the fan ramping up and down.

Thanks for your reply though.

[wpoll]

The square wave signal (PWM) is supplied directly from the the DDE (the engine ECU) so its not likely to be the problem. I suppose it could be a wiring fault between the DDE and the aux fan.

You can perform a basic test of the PWM signal with a voltmeter - the voltmeter will simply display the average DC for the square wave signal. Using INPA, turn on the e-blower (F1) and watch the meter read a higher voltage (maybe 10-11v). Turning off the e-blower should produce a drop in voltage (down to 0-1v).

[kanewesley]

Excellent Bud !

I will try that, although I didn't expect the waveform to have such a high peak to peak voltage where it could be measured my a voltmeter...however...I'll give it a go !

[wpoll]

The PWM (square wave) signal is a 12v peak-to-peak signal. At 50% duty cycle an analogue voltmeter should indicate around 6v - not that you can see this on the e-blower test, as it's only 0% or 100%.

Are you sure it was over-heating that damaged your A/C compressor? There are a lot of safety protection lockouts that would have to fail before this would occur. The variable compressors (Calsonic?) in these cars are known to fail regularly, even if the aux fan is still working....