1990 300D 180K miles

My blower motor stopped working a few weeks back. Replaced the motor. Now the motor runs at only one speed, regardless of what setting I use on the AC Control Panel (The "O" button does stop the motor)

I checked the voltages from the 3 wire plug at firewall, above the brake booster. One side has 12V the other side has 6V. The 6V side does not change regardless of what position I use on the AC Control Panel. I replaced the AC Control Panel but there was no change in function and returned the panel.

Both fuses are OK.

Someone please give me some help here. It's pushing 100F and isn't going to stop for the next month.

Thanks for any advice.

Dan