Porsche 944 Fan Runs at Speed 4 only - Resistor Cleaning with Vinegar

When I bought my Porsche 944 the interior heater fan would only run at full speed on setting 4, the rest of the speeds did nothing. Reading up I found that the resistor pack could corrode over time so that only highest speed worked.

There were various posts online suggesting that cleaning the resistor pack with Vinegar could fix the problem. It seemed somewhat bizarre but with nothing to lose I bought a bottle of vinegar, found a suitable dish and left the resistor to fizz for a couple of hours. I then washed it off, dried it and left overnight to fully dry out.

After refitting under the bonnet I tried the heater fan again - magically it now works on all 4 settings! A very cheap and easy fix!

Porsche 944 Fan Runs at Speed 4 only - Resistor Cleaning with Vinegar