Audi28A4

Okie, so the other day I noticed heater wasn't working correctly! The control unit seemed to be working correctly increasing the fan speed as the car warmed up, however there was no fan noise. I played around with the unit switching the vents which the heat is sent to and was finally able to get the fan to kick in! It worked the rest of that ride.

The next day I drove the car again and the same thing happened, no fan! I tried everything to get the fan to come on, no luck.

The following day I checked fuses, replacing the one for the blower. I turned the car on and it ran fine, I thought I had fixed the problem!

Until the next morning, fan would not turn on once again! It appears that the fan does not work when the temp is below 40 degrees outside and works just fine when it's above 40 degrees out side...

I did all the checks and believe the heater core is working fine, I think the problem is a wiring problem or the heater blow motor. What tests can I do to find out what's going on with my heater!!!?

Thank you so much for input and help!

dorsal900

Next time the blower isn't running, probe the electrical connector with a voltmeter: if there is voltage across the motor and it's not turning, there is something wrong - it's either dead or the motor brushes have worn down. I replaced the blower motor on my 1996 two years ago - it's not trivial, but you don't need to disassemble the complete dashboard. Be sure to buy a genuine Valeo replacement part - I got to do this job twice when using poor replacement part passed off by the supplier as genuine.