Recirculating air

[jdt10768]

My HVAC fan now turns on to what seems like speed 1 if the fan speed knob is set to off and I press the recirc button. It's a 91 318i and the switch is from an unknown year.

Yes, that's what should happen - turn on recirc and low speed fan starts up

[jeffnhiscars]

I checked the wiring diagram and the recirc button does fire the blower on low speed. Good catch.

[roguetoaster]

Yes, that's what should happen - turn on recirc and low speed fan starts up

I do now wonder if there is a difference in switches as my previous switch has an AC button failure, yet recirc functioned without activating the fan.

[jeffnhiscars]

I do now wonder if there is a difference in switches as my previous switch has an AC button failure, yet recirc functioned without activating the fan.

There are 2 sets of contacts on the recirc side of the switch (separate from the AC side) with one going to the recirc flap motor relays and the other to blower 1. A bad contact on the blower resistor contact would fit your symptoms

[c0rbin9]

Random but I love how the A/C buttons feel on the E30.