I have an 85 W126 which does not have the separate "recirculate" feature, therefore to invoke recirculate I have to drop my temp wheel all the way to blue. As a result, the fan is always blowing on the second-highest setting, which is often too high. If I hit the "low" fan button, it is often too low. I need to get somewhere right in between. So I was thinking of tapping into the wiring for the blower motor and adding a resistor to slow the fan down a bit. I would have a toggle that would switch the circuit back and forth between normal and resistor.

1. Any suggestions on where I can tap into the blower motor wiring?
2. Any suggestions on the resistance value I should use? How about a rotary pot? Infinitely variable would be pretty neat.
3. Any idea where I can get a schematic?

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280