Climate Controller Part number Question - PeachParts Mercedes-Benz Forum

Aquaticedge · #1 05-27-2010, 12:00 PM

I have 2 Climate Control Units,

124 830 33 85

124 830 21 85

Are these interchangeable?

Jeremy5848 · #2 05-27-2010, 12:09 PM

I would say yes. I have a "33 85" and an "02 85" and they interchange in my '87 300D Turbo (W124, OM603). The third set of digits (the "33" and the "21") represent versions or modifications to the same component. Small changes are often made during or between production runs and the version number is changed to reflect this change. Mercedes had two different companies built the CCU and the numbers could also reflect this difference. Some CCUs have a Fahrenheit temperature dial while others are marked in Celsius. This will result in a different part number. Nonetheless, the various units should all interchange as long as the other digits (124 830 XX 85) are the same.

Aquaticedge · #3 05-27-2010, 12:18 PM

the Strange thing is when I ran both part numbers through Fastlane I think it was, both came up as Celsius units, the 33 is defiantly Fahrenheit while 21 is defiantly Celsius.. Strange. I do have reason to believe that someone had been working on the CCU, it had been opened before..

babymog · #4 05-27-2010, 01:13 PM

You do not want the original Bosch unit, there was a problem with failing solder joints. The Bosch unit seems to get a mind of its own when it fails, running the compressor when off, etc.

Aquaticedge · #5 05-27-2010, 01:15 PM

which is the original, 21? the 33 also says bosch on it

babymog · #6 05-27-2010, 01:29 PM

I don't know, I no longer have any original '87 ones, ... just a stack of later ones.

Aquaticedge · #7 05-27-2010, 02:18 PM

I'll use the 33 and see what happens..

Jeremy5848 · #8 05-27-2010, 02:31 PM

My '87 300D Turbo (W124, OM603, build date July 1986) came with a 124 830 02 85 Bosch Pushbutton Unit ("PBU") and a Celsius temperature dial. I recently replaced this PBU with one from the local Pick and Pull.

The replacement unit is also Bosch, has part number 124 830 33 85, and has a Fahrenheit temperature dial. This PBU came from a 1992 300E (gasser) and seems to respond slightly faster when I change the temperature dial. Otherwise they appear to me to be identical.

According to the 1986 "Introduction into service" manual for the W124 series [section 83 "Automatic Climate Control," page 277], Mercedes contracted with both Kammerer (symbol "MK") and Bosch to make the PBU. [I've never seen a Kammerer PBU.]

In case of a short circuit (such as the aux coolant pump) the Kammerer PBU will shut off only the offending circuit until the short has been repaired, then switch back on within 30 seconds. The Bosch PBU, OTOH, shuts off all outputs except for the blower, and switches them on again within 30 seconds after the short is removed. So says the manual.

I do not know if Mercedes made a "command decision" to make all sold-in-USA W124s with Fahrenheit temperature dials after a certain date. Later cars I've seen do seem to be Fahrenheit rather than Celsius. Between the outside temperature display, the PBU dial, and the coolant temperature gauge in the instrument cluster, there are six possible Fahrenheit/Celsius combinations.

Jeremy

Aquaticedge · #9 05-27-2010, 02:42 PM

the latest one, the one I've transferred the buttons to came from a 95 320TE wagon, I grabbed it has a afterthought and diddnt do much with it, now I've cleaned it up and will put it in my car when I get a dash etc

darkman · #10 05-29-2010, 01:19 PM

I didn't want to start a new thread since push button unit numbers are
already being discussed. I have 2 other part variations to add and ask about.

I had a reman 124 830 18 85 that I replaced yesterday with a
gasser part 124 830 08 85 that I found at PickNPull. Later I read that the gasser
PBU isn't fully interchangeable with diesels. Then I found this thread and Jeremy's
comments seem to indicate otherwise.

My "new" unit (08) seems to be working normally but the A/C doesn't blow
cold. It wasn't blowing cold before the last unit failed so I can't tell if that's
because of the PBU or not (I don't think so).

These part numbers come from a reman company called Programa. I'd never
heard of them so I looked them up. On their website they claim to be "the industry leader
in re-manufacturing of European Automotive Electronics Modules since 1992".
http://www.programainc.com/

They have some pretty good info (I thought) on troubleshooting the related
CC components before installing the reman units. Here are the links for the
diesel and gasser units if anyone is interested:
Diesel unit--> 124 830 18 85 Gasser--> 124 830 08 85

So my question is whether anyone is having trouble with the A/C after a PBU swap?
(I noticed Jeremy swapped up to a 1992 gasser. Mine was '87 to '87)

Thanks for any thoughts and suggestions

babymog · #11 05-29-2010, 08:07 PM

I put a used '91 300TE PBU/CCU in my '87 300D, it worked great on heat and A/C (all functions), and cooled very well (R-12). I ran it that way for a year or so until I sold it, never had a problem.

Yes, I too have read that they are different and incompatible, apparently my car didn't know that.

Aquaticedge · #12 05-29-2010, 08:19 PM

we shall see if this one works. I'll be Disappointed if it dosnt. its buttons work better and the dial and buttons are less worn

darkman · #13 05-29-2010, 08:47 PM

Babymog,

Thanks for that information. I'm hoping that if the unit isn't working it's
because I need a A/C flush or something. If not, maybe I need to get a unit
from a '91 or '92.

They're having the 1/2 price weekend sale at my local PNP. I got the gasser
unit for $13. I think there might have been a '91 on the lot. I'll check on that
tomorrow.

And thanks Acquaticedge for starting this thread when you did.

Aquaticedge · #14 05-29-2010, 08:54 PM

Denada,

Jeremy5848 · #15 05-30-2010, 12:00 AM

I just now thought to look in EPC. For the version I got from Pick and Pull out of a gasser and put in my diesel, part number 124 830 33 85, EPC says it fits (among other 124s) the 300E, the E320, the 300D 2.5 Turbo, and the E300.

For the original PBU in my '87, part number 124 830 02 85, EPC says it fits the 300E and the 300D as well as the 4-Matic models and models we rarely got like the 200E, the 230E, and the 260E plus the 200D and the 250D.

So it would appear that the same PBU fits both gassers and diesels. This can also be inferred from the 1986 "Introduction" manual since it describes both diesel and gasoline versions of the W124 model but in the climate control section doesn't say anything about different versions for the different cars.

There must be differences between the various part numbers but apparently nothing that would prevent different PBU model numbers from being interchangeable.

Jeremy