'83 manual heater issue

[911carl]

Hi,

Suddenly both the fresh air and heat blower stopped working on my 911 SC '83 with manual heating system (red levers between the seats).

I checked the heat blower by making a bridge between terminal 30 and 87 on relay 30 and the fan is still working. I then measured the voltage between fuse 2 and relay plug pin 85 and no difference is noted with the levers on or off. I checked the swith on the levers and this still looks good.

It's strange that both the fresh air and heat blower fail at the same time as this should be independent systems, right? I'm pretty sure that I always had to turn on the fresh air blower in order to get the heat blower working in the past as well. So I'm starting to think that someone messed up the electrical system in the past.
Any thoughts on how to proceed?

Thanks!

[911carl]

Anyone? I'm not a great electrician...

[rick-l]

I don't have an 84 but is there 12 volts at relay socket pin 86 with the key on? Can you put a test light on pin 85 (one side to 12 Volts) and see if it lights with the levers up?