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'86 190E 2.3 8vlv
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Discussion Starter #1
My aux fan does not come on even when my coolant temp goes well above 100C, or when the AC is on.

It must be either the aux fan switch or the relay (I think).

1. Is the aux fan switch the one with the dark orange top in the pic below?

2. Is there a way to test the relay? A way to jumper it to turn on the fan circuit?

I am starting to bond with this car after owning it two months...I like the look and ride of it. I hope that I am sorting out the problems and that there won't be too many new ones.

It looks pretty good, but not as good in real life as it does in this photo.

http://geocities.com/japrizzi/home/190_rr_qtr.jpg

Anyway, here's the alleged aux fan switch.
 

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'01 SLK230,'93 190E 2.3, 1971 LS5 Corvette Convertible
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2,225 Posts
joebob2,

First of all, I assume that you are referring to the electric aux. fan in front of the condensor coil. If so, make sure that the fuse is good. I went through the same problem a couple of years ago and it was a blown aux. fuse.
If the aux. fan doesn't come on when the AC is on, the high pressure switch on the AC receiver/dryer will shut off the AC compressor when the high side gets too high.
Yes, that is the Fan Clutch, Aux. Fan, Temperature Switch in the photo. It should be Red, Three Prong, 100 degree C., up to 1987 model year.

You have a good methodical mind. [;)]

Good Luck,

Dave
 

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2000 C230 Komp
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182 Posts
Most likely the fan motors have debris stuck between them. If the nothing as far as electrical leads you to a solution, remove the fans, then remove the motor from the fan/blade assembly and disassemble the motor. Make sure that the circuitry inside hasnt been burnt out. If not then just clean the insides and use some WD-40 or anyother 'electical safe' solvent to clean the motor. Reassemble and test motor with car battery terminals.

This should get the motor spinning again. If the motor doesnt spin, the circuits are fried. This has happened to me. If its not fried then the regulator (brush) inside the motor must be worn down to a point where it can no longer make contact with the coil surface. This has happened to me also.

All the best.

p.s. i picked up a used pair of motors with fans for around $30.
 

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'86 190E 2.3 8vlv
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Discussion Starter #4
slk230red - 4/27/2005 7:11 PM

First of all, I assume that you are referring to the electric aux. fan in front of the condensor coil...make sure that the fuse is good...the high pressure switch on the AC receiver/dryer will shut off the AC compressor when the high side gets too high.
slk230red-

Yes, I am referring to the elec. aux. fan. The fuse was fine. I know that they need to be turned from time to time, and do that every time I check something.

As far as the AC receiver/dryer, I may need to ask for more info.

There are two switches on it...one red one near the top, and one lower down, with a ceramic piece on top.

I do have continuity across the lower switch, which means it is OK. I didn't check anything on the upper switch. Is that the one you were referring to? If so, how should I check it?

I'm not religious, but maybe I should become a methodist....

mykg4orce - 4/27/2005 10:14 PM

mykg4orce-

Most likely the fan motors...
I checked the aux fan by hooking up leads from the battery directly, and it ran just fine, so it's back to the switch/relay solution.

Thanks for the info. I now know that a fan isn't as expensive as I thought.

Joe
 

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'01 SLK230,'93 190E 2.3, 1971 LS5 Corvette Convertible
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2,225 Posts
joebob2,

Since you are now a relay expert, did you check the aux. fan relay at the fuse box? It should be the center one behind the fuses.
If you haven't already done so, call Performance Products and get a parts catalog for your model. The pictures and prices come in handy. 1-800-243-1220

Also, be sure to check out this website:

http://mb.braingears.com

Dave
 
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