Dan's 1993 190E

Hello All,

I bought my car about 5 years ago and the a/c died after the first year. I looked at sites like this and saw so many references to common problems with the a/c that I figured I wouldn't bother to fix it.

Now I want to fix it, but I can't find any mention of these problems.

I did take it in for a recharge last year, and they said that it was fully charged and most likely blocked somewhere. Again, I was frustrated and just gave up.

Anyone that knows of specific 190E a/c problems please post some troubleshooting hints.

In particular, I'm curious as to how I would know if I need a new climate control box thingy (buttons and dials on the dashboard).

I'm very mechanically inclined, but I know absolutely nothing about a/c so be kind with the high tech lingo!

Thanks,
Dan

sosh

Could be the evaporator drier needs to be changed. Best bet is to bite the bullet and go to either an MB dealer or a Good automotive air cond. shop, not a general repair shop

electric blue

No disrepect to Sosh but i think going to the dealer with your ac problem will cost you a great deal of money. Do you really want to pay over 100 dollars per hour labor rate on ac repair. If you have to replace your evaporator core you could be looking at over 2000.00 at the dealer. On that job the dash has to be removed, that's something like 20 hours labor.........Ouch!!!!!!!!!.. If you can tell me more about your ac problem i can guide you in the right direction.

Dan's 1993 190E

I'll give the car a little attention and try to take some notes about what it does and doesn't do. I'm one of those weirdos who refuses to pay anyone for something I can screw up myself! It's a good thing that home dentistry equipment isn't readily available! I'm just not 100% sure of what symtoms to look for.

Dan

Rod Spohn

Dan, My 190e had A/C problems also. Do you hear a clicking sound sometimes, in particular when trying to mess with A/C switches? Behind the glove box & to the right is a electrical/vaccum controler that controls the switches you push or move on the dash. check that out first. Its fairly easy to get to and is quite common couse of problems. Hope this helps.
RCS

Dan's 1993 190E

1. In regards to the climate control module in the dashboard:
Each button I press lights up as it should
Each button does what it should except for the a/c and dehumidifier
Nothing makes the compressor come on
2. Under the hood:
Hoses look new and in good shape
Drier looks old
Auxillary fan switch shows severe corrosion at pigtail connection
Freon pressure sensor looks as old as the drier.

3. Would it be stupid to replace the drier and switches mentioned above and give it a try? Or should I do more? For instance, is it possible/necessary/worth it to add oil to the compressor? The hoses are in great shape and the shop said it was fully charged, so I would "assume" that there is little risk of the compressor lacking oil. Would it hurt anything if I just replaced the switches before I replace the drier? I really don't want to get into disconnecting hoses since the problems seems to be electrical.

4. I'm looking at an exploded diagram and I see the expansion valve, but the diagram doesn't relate which side of the firewall it's on (I assume on the passenger side in the least convient location for a $25 part).


Rod,
This electrical vacuum dohicky, do I take the glove box out to find it? I don't hear any noises at all when I push the buttons.
Thanks,
Dan

Rod Spohn

Dan, Yes take out the clove box (easy) then to the right & is fastened to the inside of the dash. You will see several Vac. Hoses & 2 Elct connections.
As to your other Question about the sensors! My thought is yes compaired with the cost of other main part. I always start with the low cost items first and work up. most repair shops like to replace most everything before they will warrenty there work. So if you end up at a shop you have saved a fortune by doing that yourself. But nothing hurts more that to change a high cost part only to find a Cheep relay , sensor , fuss. OK now you have my ten cents worth. your a smart guy ( clutch is turned on by elect impulse So check sending units then compressor. If its not engaging I'd concentrait on that ) PS the switch you are looking for is behind the Battery on mine.

MTI

On the W201, the evaporator is on the engine side of the firewall, not on the interior side, where the heater core is located, so you don't have to pull the dash to R&R the evap core. You do have to remove the wiper arm, the debris sheild and the blower motor housing.

If you can't hear the vaccum actuators opening or closing the vent doors, then that's a pretty common fault. However, I would say that most a/c system repair work is better left to a qualified shop with the proper test tools, especially if you don't know the high pressure side from the low.

electric blue

MY Mistake......Your absolutely correct on the location and how to remove the evaporator core. I was thinking of the S class Mercedes and how difficult they can be.

Dan's 1993 190E

I plan to buy the following items:
1. receiver drier
2. freon pressure sensor
3. auxiliary fan switch
4. expansion valve
5. three-way check valve

Two other items, the compressor/clutch and the compressor relay, I would like to test first.

Is there a way for a DIYer to do this, like jumpers on the compressor or a meter for the relay?

Can a good a/c mechanic bench test this stuff and return my car in one day?

I know the perfect a/c mechanic, but he is obsessive compulsive. That's an excellent quality to have in a mechanic, but he will stop the entire job and move on to the next vehicle if he finds something along the way that should be replaced. With that in mind, I don't want to surrender the car to him without doing all I can to provide him with as many parts as I can afford.

Thanks,
Dan