Hi Techs out here,

I need help for my '82 W123. It is a Euro model with air-con knobs. The fan speeds 1 and 2 do not work at all, but the highest speed 3 does. I am quite sure the compressor and coil are fine as the engine idle does change when the air-con knob to turned to both 1 and 2.

I have been told that the 'resistor' of te air con unit is faulty and I should replace it. I need help for the part number (if my diagnosis is right).

On a separate matter, can anyone identify this part number 123 540 0369 ?

Many Thanks!

Hi all,

I am still puzzled and stuck, can someone out there please help, it is terrible having no air con, or full blast cold air right at yyour face. :(

Any help is most appreciated!!!

Hi everyone,

Seems that I am writing my own thread, Benzmac, where r u when you are so desparately needed!

Anyway, I have stripped down the dashboard to assess to the air con unit. I have changed the blower fan thinking that the fan may have gone south, but no, the fan speeds 1 and 2 are still not working. :(

I now need very desparately, any pictures or diagram depicting the resistor that controls the fan speeds, so that I can accomplish this task sooner. I would truly truly appreciate if somebody out there please help. :)

Thanks everyone.

I have seen instances where the contacts in the rotary fan speed control switch are the culprits. Check those for continuity first.

I have two Euro 240D's, both have an aftermarket a/c. Are you sure yours is not aftermarket. On mine the resistor assembly is on the air duct below the evaporator. A couple of wires are connected there. Yes, the switch will have to be in good shape as well. Neither the switch, nor the resistors have ever given any trouble.

If your Euro has MB air, it would be quite unusual.

Good luck,

Hey Guys,

Thanks for the replies, I am pretty sure that my air-con is not an aftermarket unit as everything there has some mb part numbers on them, besides, the other units that I am sourcing from the local scrappies are exactly the same as mine.

I have gotten two other switches from the yard, and none of them seem to solve my problem, thus indicating that my switch is fine. Swapped the blower fan too, but no bingo. I can't say that I am awfully ethusiastic to remove my dash to get to the resistor, as I just did a dash swap a couple of months back, so I am seeking help if anyone could tell me exactly where the resistor is and how it looks like (that is most important to me!), or any mb part numbers. The scrappies are not too happy if I were to strip their cars and I cant find what I exactly want.

Larry and toohot, it is just great to hear your replies, I would be very grateful if you could help me with some description of the resistor. (It should be some mb part with some numbers on them I think!) :)

Hey Guys,

I have found out where the resistor lies, its right below the front valance where the wipers are, but I hasten to add that accessing the resistor has taken off a few years of my life, since I started by removing the dashboard. On well! :)

Anyway, the resistor was not damaged but was not functioning as the entire valance area was flooded with water, causing the circuit to short out. Hmm, i wonder how water ever got in there anyhoo. Any clues??

Sure hope that this tip is useful for anyone having the same problem as mine. Anyone out there with a spare W123 aircon resistor?? Sure appreciate one to replace my corroded one.