I did a couple of searches but couldn't find what I needed. My electric fans don't seem to coming on with the ac anymore. I hoping it's something simple like a fuse. In the fusebox there is one for auxiliary fan which looks fine, but I thought there was another one somewhere. Fans seem to spin freely, but I haven't tries applying 12v to it yet. Any other ideas? It seems to dramatically effect ac performance!

Thanks!

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I'm assuming it's one of your Mercedes? If the 124, check the high-pressure switch on the filter/dryer (it turns on the fans), and the ceramic resistor behind the driver's headlamp.

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Gone to the dark side

- Jeff

Okay, I jumpered the pigtail leads near the drier and the fans kicked on. So, does that the switch is bad? Does replacement require discharging and recharging of the ac system?

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I'll keep searching for answers, but if anybody has anything to add that would be much appreciated!

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It helps if you give a hint as to the make, model and year of car.

1995 E300D 216k black/mushroom

The make, model and year of the one car I own is on every post I've ever posted, as well as the one Mercedes I used to own, indicated by the (sold) after to description of said vehicle. I was instructed early on in my posting career to include this information, lest I be asked what vehicle I have questions about, and make it easier for friendly and knowledgeable people to help me. So can someone please explain to me why two veterans of this venerated forum have asked me what make, model, and year vehicle I am referring to? This is truly baffling to me.

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Okay, I was able to do some more reading and learned a few more things. My refrigerant could be low, and not triggering the high pressure switch. Also, that the fans don't necessarily always turn on when the ac is switched on, it can depend on other things like thermal load of the ac and engine temperature. And since the fans turn on when jumpered, that it indicates that the fuses and relays are in working order.

Since I have not seen the fans operate properly in various conditions now, I suppose I have to assume it is a bad ac temp switch or low refrigerant. Can I replace the temp switch without depressurizing the ac system?

Any other ideas? Thanks.

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a HUGE majority of the posters here have their CP settings configured to block signatures so annoying things like on mine do not show.
it's always best to post what vehicle you are asking about in the body of the thread you start. because if you change your sig, all posts sig lines change too. so if you asked about your SD, and 5 years from now, you have a GL, anybody reading your post for help would get confused.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I agree with your conclusion, check pressures first, then the switch if pressures were correct. I don't remember the cut-in pressure of the switch.

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Gone to the dark side

- Jeff

That explains a lot, thank you. I didn't know you could block other peoples sigs.

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This is a '95 e300

Okay, so I've been pretty busy lately but temps are rising so I need to get this fixed. I received the ac temp switch from Fastlane, but when I went to replace it brown fluid started spraying out! I guess I had it wrong, I though it was the pressure switch that would lose refrigerant if taken off. Can anyone shed any light on this? I don't have the tools to check pressures, so I opted to get the part first. Should I give up trying to fix it myself and just go to an ac shop?

Thanks!

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could be a bad relay. . .

mine was bad like 2 years ago. but I suspect something else has gone amiss lately. need to re-check the system myself

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87' 300DT (Grey w/ red leather)
87' 300TDT (silver w/ palamino tex) SOLD

2012 VW JSW TDI (on tdiclub.com all the time "btcost")

In case anyone is curious I just had it checked out and re-filled by a local a/c guy. He said there were no significant leaks and now it is working like a charm. $100. Done and done.

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