jettskiman

I have an 86 300E (US) and the heat is on all the time unless you turn the control all the way to ac. I've been reading some of the posts about this problem and found a good one from cap'n jasper about the mono valve. I also found a page in my Bently E class owners bible that say the (m13) coolant pump may be bad. Is this the mono valve, the one right next to the battery?( see pic) I got one off an 89 in the wrecking yard but still have the same problem. I took the old one apart and the rubber diaphram seems to be shot allowing water to get into the solenoid plunger. its probably the same problem with the one off the 89 thats on the car now. This valve seems like an on and off valve though, it seems that when its closed you would not get any water and thus that air should blow cold or outside air temp. How would it regulate temp if the control is set to say medium. Does it cycle open and shut a lot. This one doesnt have rubber in the valve. Just a brass thing that seats against a base when closed. I put 12 volts to it and it does close but this is out of the car with no water presure on it. As for the auxiliary pump, should I be able to feel it running with just the ignition switch on or do I have to have the motor running?
You can read the paragraph from the Bible just under the valve, is this right? Any input would sure Help.

ALL E-CLASS AUTOMATIC CLIMATE CONTROL PROVIDES ONLY MAXIMUM HEATING UNLESS TEMP WHEEL IS SET TO MIN...current draw of auxiliary coolant pump(m13) is above 0.8A or pump is seized. This triggers short circuit protection feature in A/C control panel. Current to aux. coolant pump and coolant monovalve is interupted. Turn ignition on and set temp wheel to MAX. a. Touch auxiliary coolent pump to check if running. if not replace pump. b. Check current draw of auxiliary pump, if over 0.8A replace pump.