124 Blower fan R&R -big mess!!!
 

OMG, WTF? I followed the photo thread quite exactly and all went as it should . Motor had been squeaky so I took it out and carefully lubed the bearings. I let it run for a while with the cover off and then put the whole thing back together. Now fan runs at slow speed, at ALL times in ALL modes, even the "O" setting.
Here's the worts part---car will not start! Battery OK all the lights come on, starter won't click-nothing! (I did smack the relay-type thing behind the motor clip when re-installing the fan motor)??
Help please.
thanks CC

I think there is a connector on the firewall, more towards the drivers side, that is for the crank signal to the starter, possibly was disconnected and needs to be reconnected?

I also wonder if you got a couple of those connectors on the firewall reversed, which would explain the fan running even in the off mode.

I should say that this is a 1995 E320. I now have the blower motor back out of the car and regulator unplugged. Maybe I just ran the battery flat??. Trying a jump right now.

OK. batt. was flat from running blower. Duh. Back together & on the charger. We will see about blower motor in the AM. Thanx to Gilly for ideas.
CC

Gilly has nailed it. Those are the two possibilities.

The blower has three wires -- hot, ground, and control. If the control wire is disconnected, the control lead of the big transistor on the porcupine heatsink will float high enough to partially turn on. That would run the blower in low speed all the time, as the blower gets power whenever the ignition is on, even if the PBU is off.

Jeremy

No squeak
 

Battery charged over night and car started right up. Blower fan smooth & quiet in all modes. Cabin still smells like PB Blaster but with new filters should dissipate. Hoping bearing lube will hold for a while.
thanx to all
CC

What did you use to lube the bearings? I need to do mine.

ATF seems to be a common suggestion.