Help me test blower regulator

[rsheely]

I've done a search but am not getting anything precisely for 124s.

My fan fluctuates up & down. I plan to replace the brushes in the blower motor but am unsure how to test the blower regulator. I'm aware of it's location and wiring but just don't know test procedures. Would someone please be kind enough to give me a simple explanation of how to test the blower regulator. Also, I'm assuming it's only operational when the climate control is set to auto vs. low or high?

BTW, this site is awesome! Guys like GSXR, Hatterasguy, & Bilble are radical & have kept me from asking thousands of other questions.

Robert

[HGV]

The blower regulator is located under the blower and is a solid state device and as such is not simple to test. Your intermitant blower operation could be related to a cracked fuse buss. Not knowing what year or model you have this might not be applicable. On my 95 E320 wagon, there is an auxiallary fuse buss located outside of the fuse panel. It has a knurled cap. THe one on my car was cracked and made intermitant contact. Following the repair the blower regulator went bad and I replaced the blower and regulator at the same time. It takes about four hours and is rather involved but straight forward. I have done it on an 87 300TD and the 95. Most important is to be methodilcal and make sure you place the weather striping in the order that you removed it placing close attention to details, like which piece goes in first. Also when removing the wiper motor support, don't drop the nuts into the blower air supply as it is impossible to retrieve. When placing the strap that holds the blower motor inplace, make sure that it locks firmly or you will do the whole thing over again. Don't ask how I know. Also, all the plastic parts that act as heat shields on the fire wall are brittle and easy to crack. Be careful and if you crack anything, have some super glue ready. THe weather stripping on the 95 snaps into a plastic V groove on the window frame. Remove by gently prying up off of the glass. Protect the glass first and gently pull the weather stripping from right to left while prying up.

THe blower is operational on high auto and low. The voltage is changed depending on switch positon or control logic. It is all solid state and not that easy to test. Usually if it is the blower control, it will not work on any setting..

Let me know the particulars on your car.

Henry

[rsheely]

Thanks for the advice Henry. It's great to confer with someone located in the Bay Area. I just moved to Santa Cruz after living in S.F. for 12 years.

Anyway, I own an '87 300TD & love it. I've already carefully removed all the necessary parts (wiper, blower, etc.) & can cleary see & touch the blower regulator. Also am aware of where it plugs in behind the brake master cyclinder. I've got my volt meter & just need to test it before I reinstall everything. I assume I can test for certain amounts of voltage when the fan is set to low, high, or auto but unfortunately don't know each respective required minimum voltage. Thanks again & if you ever need any specialized MBZ tools I'd be happy to loan them to you.

Robert

[HGV]

I have the info at home for the 87 300TD. At least I think I do. I will take a look and let you know what I have. Send me your email or send me a PM with it, that way I can send you a PDF of the relevent data.

Henry