Sorry about closing the thread! First time on here. I'll learn and write it once more since I really need a couple of answers.
It started as the blower from the climate control started getting weaker over the past two years until it finally failed. I had bought a climate control from a car being parted out, installed it and it did not make a difference. When you press the buttons, you can tell it switches between heat and a/c, but does not blow air. The fuses are fine, and the strip fuse outside the fuse panel is intact. I would like to know how to hook the blower up directly to the battery to see if it operates? Do you just hook up two wires to the motor and check, or do you have to unhook the other wires on the unit first? If the motor runs, is it the regulator? Before I attempt all of the work of removing the wiper arm assembly, could it be the relay instead? If so, how do you check the relay?

Thank you in advance for any $ saving suggestions!

I have same problem and have thread going on tech help. please review and add what you find.

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What relay .. there is no relay.
You check for power at the 3 prong conector behind the booster. Red/blk is 12v power and y/blk is variable power [ 2-8v] for regulator trigger. If both are good, ground blu wire at regulator to complete the switched ground circuit. If blower works, reg is bad.

The regulator needs variable trigger voltage to complete the blowers ground side [ neg.]to operate. That is what the trigger voltage does.. it activates the switching transistor , which completes the blowers ground .. the hot side of blower is always hot . The switching is done by the reg on the GROUND side. So, by grounding the blu wire , you are taking the reg out of the circuit and will have direct/full speed fan.
There are NO resistors.

Thanks for all suggestions on Blower Motor on 1991 300 E. It is fixed. The protocol I listed workede quite well in Identifying the Blower Motor regulator as the "Bad Actor" 1.) 12 Volt Battery supply voltage spun the motor.
2.) Getting 12 Volt reading from motor supply wires ( apparent low amperage as 1 amp fused short would not even blow the fuse from this 12 volt supply.

3. Running a supply wire from the terminals from behind the fuse block Master Cylinder spins motor

4. This step bypassed the blower regulator.

5. Found one (over phone )for $10.00 in salvage yard but since he had to remove blower motor to get to it I had to take the blower as well for a total of $ 75.00. (It looked better than the one I had.

I was corrected by someone that Regulator was "not" a series of resistors and I did know that. I was simplifying its function in the circuitry. I suspected a lot of resistance activity in the the tiny pitch pot as it is attached to a huge (relative to its size) aluminum Heat sink (Porcupine)

More good news! Junk dealer had a broken (parts unit) Windshield wiper transmission that I got a replacement circular rack gear and restored the oscillating feature to my wipers.

Finishes up another project working on these wonderfully designed cars that can still frustrate you when the designs are unique or we don't fully understand (or appreciate them) until we have them figured out.

Thanks a Bunch,
Don

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Is that why you asked for Ohm values??

Next time , simply groumd the blu wire as was suggested .. that takes the reg out of the circuit without having to run any wires back as you did.