Well, my dandy little $10 AC servo worked great for 6 months and kicked the bucket. I bypassed the coolant valve and installed a manual valve, controlled by a throttle cable under the dash. All was working well until it actually got cold. Now the blower won't come on. I know the switch on the bottom of the servo senses when the coolant is warm enough for heat, but does it cut the blower on and off, or the aux. coolant pump? I'm thinking of bypassing the blower controls and installing a rheostat to control the fan speed. Any advice or ideas??

Thanks

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1980 300d on veggie

Fix it correctly to OEM standard function...

You did ask.

Have a great day.

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does the blower work on defrost?if not you could be right about the coolant temp switch.if blower works in defrost only you have a vacuum leak in the climate control

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michael cole 1980 300SD gone now but not forgotten,87tdt,90 300te 4matic 95 e320 wagon

Well, if OEM standards didn't involve the biggest piece of crap component Mercedes ever made, I might do that. I don't have $600 to shell out for an Unwired tools replacement, so I guess I'll do it this way.

The blower doesn't work in any position, so I guess that's it.

Thanks

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1980 300d on veggie

Well said. This is a textbook case of planned obsolescence. High dollar (to consumer) simple fixes must be a car dealer's dream. I'd like to see a thread on nice ACC hacks.

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What Would Rudolph Do?
1975 300D, 1975 240D, 1985 300SD, 1997 300D, 2005 E320 , 2006 Toyota Prius

These blowers are known for drawing large amounts of current as the brushes wear and blowing the fuse. I would check the fuse, and since it takes about a minute to remove the blower, I would pull it out and shoot 12 volts to it and see if it works.
At that point, you will have a better direction on which way to go.......

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
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'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

OK. Test my logic here. The switch I was talking about on the bottom of the servo is simple. It has a bimetalic reed in it and 2 vacuum connections (yellow and red). When it is cold the reed closes over one of the vacuum ports and when it is warm it opens up and allows air to pass from yellow to black, or vice versa. On the way home tonight I thought if it is open whan warm all I need to do is pull the 2 vacuum lines off and connect them. This is essentially what the switch does when it is warm. I got home and tried it, so maybe it is something like JimmyL is describing. I'll let you know what happens. BTW, as far as hacks go the manual valve I put in works like a charm. I installed it in the 3/4" hose at the firewall and am running the throttle cable through a spare nipple on the big rubber electrical grommet. I'm going to put the other end of the cable just under the dash on the kickplate.

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1980 300d on veggie