So here I am trying to troubleshoot my 1986 300SDL's blower motor not working. I've got that heat-sink-looking thing on the floor and see there's a red and blue wire each going to the blower motor. I put my multimeter's + probe on the red wire and the - probe on the blue and I get 13.6V (with very slight fluctuations). Turning on the fan swich on high/auto/low does nothing to the voltage. It stays 13.6V. Assuming the blower motor provides the ground I put the + probe on the red wire and grounded the - probe and get 13.6V. Then I put the + probe on the blue wire and keep the - probe grounded and I get 0.55V. These values DO NOT CHANGE whether on the low, auto, or high-speed fan buttons. What's bad then....the blower motor or the regulator?TIA.