400SE AC/HEAT Blower/Regulator
 

I have a 1992 , 400SE, air from the ac/heat comes out very, very slow, I was told it may need the regulator replaced, since I get some air it may not be the motor or fan, I am pretty good working on cars , but never done this test,
Question: what is the best way to test this? mainly where is the regulator located, and how do I replace it?

Please help!!!!!!!!!!!!!!

John

The regulator is located on top of the blower under the cover at the right rear engine compartment. You will need a diagram but basically the regulator gets in the negative leg of the blower circuit. It is a big output transistor with the base being the control signal from the pushbutton control.

That wire is small and will have from 0 to 6v on it with 6v being max blow. If you get the six volts and only lower speed then the regulator is the problem.

One drawback in the diagnosis is that a weak blower with high current draw will shorten the life of the regulator and when you buy a blower you get a regulator. If you do a good job buying you can get a blower w/regulator for near what the dealer will want for a regulator.

Great! I guess I should just replace both as you said since I have to do the work anyway, any good ideas as to where to buy the parts for a great price?

John

Well, since you asked, if you can't find it elsewhere I could sell you a Behr blower w/regulator for 350 plus shipping. That is 28 dollars less than MB list for the regulator alone.

I could also sell you an aftermarket regulator for 160. Or a real Behr one for 210.

350 It sounds fair for the two parts, how hard will it be to replace? as I said I am pretty good with cars I just have not done any work on this one yet, my wife got a new kompressor and I got this one with a few things to repair,]

John