OT Do we have any factory Mercedes Technicians here, GLK Blower Motor/Resistor Issue Options

[seanery]

Hi guys, I have a 2012 GLK with 36,000 miles on it. The car is in great shape. Recently, I've had issues with the AC/Heat blower motor. It started to work intermittently, then stopped altogether. I read a bit online and see that is a common problem with Mercedes. The issue coming down to blower motor failure or resistor failure.

I bought a new blower motor, but before I installed it, I plugged it into the resistor in the car and it was a no go. So I ordered a resistor and had it overnighted. It showed up this morning, I tested it with the old fan, plugged both in, turned the car on and the fan worked. I packed it all up, put the bits back together and turned the car on, and no go. Right back to where I was before.

I tested the voltage coming TO the resistor and get 14.7-14.9V. I test both units outputs and get .7V. Obviously not enough to drive a van. The thing that gets me is that it did work for my 30 second test.

As for wires that go to Resistor:
1. Power
2. Common
3. Yellow wire? Sensor? I'm not sure what this does

Wires from the Resistor:
1. Power to fan connector
2. Common to fan connector

The fan control powers up, and I can hear things change when I change modes, etc...The car makes AC and heat, just doesn't blow it.

I'm in a huge timecrunch and this is baffling me! And BEHR is such a big, machine that getting a hold of someone there has proven fruitless.

Any help? Ideas?

TIA!