I have just bought a 1988 300e. In order to pass a safty check in Ontario the car must have air blown onto the front window. In my car the blower will not run. I have a manual on order but its not here yet. This is what I have done so far.
I checked the sampler motor and it sort of holds the paper to the intake hole. I have to put the paper on it just right for it to stay, but it does. I then went to the plug where the regulator plugs into the fire wall. The black ground is good when checked with a meter, the red larger red wire shows the battery value, the yellow wire shows between 5.8 and 8.5 volts with the control set to A/C on high, fan has been set to all settings. From what I have read is that if you have these readings it is the regulator or motor that is not working.
I removed the blower and and put and put 12 volts to it and it works well I think.(I was just holding it in my hand and it tried to fly away amd bit my thumb, don't do what I did, test it in its cradle.)
I put the meter onto the regulater output wires, the red and blue ones and got the battery output of 13 volts. The blower will not run.
I took a reading at the blower fuse( on left fender infront of main fuse box) and got battery output of 13 volts. This fuse was blown when I got the car so I have changed it. When I checked this with the test light it would not light. The light will not work from the regulater also.
Can anyone tell me why I seem to have the correct readings from these points but no power. I would like to try to get this working before sending it to a shop. Also is there a thread for removing the section of dash with heater controls on it. I got the window control section and the ash try part and the glove box but the heater part has me stopped. The wire from the blower comes out through the firewall goes to the fuse and back through the firewall and I was tring to track this wire down.
Thanks.
Lance.

The blower uses a switched ground from the regulator to complete the circuit.
Ground the blue wire from reg to ground and fan should run..
if it runs, reg is bad, if not , you have no power to blower live side........

What you say sounds good and I will give it a try, but can you or anyone tell me if I should have power to the blower fuse because there is no current there. The test light will not go on. So do you think if I check the ground at the motor it will make any power to this fuse.

NO
There should be power at the blower at all times , the Reg simply switches the blower to ground, so if you have no power at the fuse , you have no power at the blower ..
Check the connections at the fuse and look for hair-line cracks..if not , start chasing the feed wire to the fuse connectors........do you have the exterior fuse .. there was a change from the fuse box on later models..??

Thanks I guess I will wait to get the manual. I was thinking the fuse box is the blower fuse box but I just don't know. It had a flat metel fuse thats held in with two screws. The old fuse was toast. Its in a little black plastic holder with a fold over snap lid.

The Exterior fuse was added after serial # F023505

All they did was to put a fuse outside of the box and wire it in parallel to fuse # 12 in the fuse box..
See if there is a fuse in #12..if there is , you have the earlier style..
Key on, of course, when testing
Some of these were also converted by the owners , in which case you want to look at the wires under fuse # 12 for bad connectors..