Strange fan speed problem!
 

A couple months ago I was having a fan speed problem, after replacing the ballast resistor and ignition switch I had it fixed, my fan would run on all 4 speeds.
After driving the car I realized my temperature control wasn't working even with a new heater valve. It did work a couple times which made me think it was electrical so I ordered another (used) heater control panel. I installed it and turned the fan switch on, back to only running on setting #4! I was upset because I thought it was a bad control unit so I re-installed my old one and now it does the same thing, only works on setting #4! I checked the ballast resistor connection it was fine.
I don't think I did anything else, any idea what it could be?
Rusty

What model Porsche is it?

Sorry, it is an 86 944 Turbo. I just pulled both of my Ballast resistors out of the vinegar they were soaking in all night, I will install them and see if it helps.
The other strange thing, I accidently left the ignition switch on last night while I was starting this thread. The fan was left on the #1 setting, I went back out to the workshop and noticed the ignition was still on but strangely the fan was running! I turned it to the #2 setting and it increased in speed, tried #3 and it shut off! Took it to #4 and it came on again, I thought that would be ok, I can live without #3 but after turning it back down to 1 & 2 neither worked again!
Rusty