Wiring Woes I: heater

[Ferrance]

In my restoration of a 1972 2002 BMW, I apparently rebuilt an old style heater (three-wire); however, my '72 harness has four wires for the heater. Assuming I can use three of the four wires, how should I wire it?

(My wires: blue/black; green/yellow; blue/red; brown ground. Old wiring diagram: green/white; green/red; brown ground.)

[Jerzy]

Three speed heater -

Here's the two speed -

Depending on how you'd like your three position switch to function, there are several ways to connect the switch to the blower.

The most direct hook-up would be to match your #1 & #2 switch outputs and leave your #3 switch output wire (blue/black) disconnected. This should give your switch the function of: OFF, LO, HIGH, and another OFF.

That's my best guess.

[Ferrance]

Jerzy, re the heater wiring: That's exactly what I needed. Many thanks!

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