Heater Blower, Braking Lights, Rear Window Heater Not Working

[tmh]

Hi!

We have a Xantia '98 mod with automatic heater blower control. At first, the problem with the heater blower was intermittent. Now, the heater blower is not working at all.

 

This is what we have done so far:

When we disconnected the blower and turned the engine on, I measured 12V between the thick red and black wires in the brown 4 pin connector, and all of a sudden, the rear window heater and braking lights were working. I tried bypassing the blower's speed regulator by connecting the 12V source directly to the motor, and it works fine. We then tried connecting the blower while the engine was running. Result: the fan rotating half a round before stopping, and the braking lights plus the rear window heater stopped working, even after we again had disconnected the blower. The 12V to the blower also disappears. When we restart the engine, the braking lights and window heater are working again. Until we reconnect the blower. We tried this several times, and most of the time, we actually have to start the engine for the heater+lights to work, but sometimes it is enough to turn the ignition switch on.

 

Anyone with a clue of what is going on? Thanks a lot!