'86 300SDL - Heater Blower Fan Problem

Feb 09, 2005 2 Replies

My Heater Blower Fan has stopped working. I removed the heater blower motor and had planned to replace the brushes assuming that this might be the problem. However, after applying 12Vdc directly to the blower motor it runs fine.



I checked the female side plug that the Blower Regulator connects to and I have voltage going to the Blower Regulator.



I do not however have any voltage on the output of the Blower Regulator (Red & Blue Wires).



I am assuming therefore that the Blower Regulator may have failed. I also speculate, because I do not have a wiring schematic, that the Blower Regulator may contain only a high temperature N.C. thermal switch to shutdown the blower on over temperature. (Failed in open position).



Or is it a N.O. switch which closes when the air is up to temperature?



I want to jumper out this switch rather than buy a new Heater Regulator.



Can someone validate my reasoning as to the function of the Heater Regulator or offer another suggestion as to what else might stop the heater blower fan motor from running? Again, the motor is ok.



Thanks



Being cheap and bypassing the regulator will give you high speed only. The small wire going to it comes from the pushbutton unit and the voltage from the pushbutton is what varies the blower speed. You have a stepless speed system. Low voltage in = low blower speed.

The cilmate control pushbutton assembly has failed. They do that. A lot.

Get a good used one (around $50) rebuilt ones are about $300, don't ask what a new one costs.

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