R129 Climate control unit part no replacement

[MD5]

I don't know if I have bought a faulty second hand unit or not, or if it's due to incompatibility (and not sure where to post this)?

Part no 2028301285 for the climate control unit in a 129 (below) has been replaced by part no 2028301385. Does anyone know if the older part no is forward compatible with newer cars please? I have replaced newer with older, which works fine, apart from the hot and cold illuminated switches in the centre vent above. These remain lit whilst the heater is switched off, and aren't properly controllable, as they are with the later one being replaced. Anyone know?

 

[Sp!ke]

In the back of my mind I'm pretty sure there was a thread on Benzworld about this and they arent compatible.

I'm not 100% sure, but reasonably so.

What is wrong with your original unit?

 

[andy27168]

Hi,
I don,t have a 129 but I have a 202 which shared the same climate control unit and I replaced mine for a slightly different part number (same pt no's you quoted I think) with no issues the unit I put in was from a slightly later 202 so I just thought the pt. no. showed it had been superseded, possibly updated software or something to fix the all to common pixelated display which sadly is present on both of mine.
I will check on the EPC for the 202, 129 and the units I have here for pt no's, Based on my experience I would say you shouldn't have no problems.

 

[MD5]

Thanks Spike. The later one with the 13 part no. works perfectly with occasional ghosting in the window display (ambient temp dependent?), but the earlier one, with the 12 part no, has an erratic switch panel, and the controls are uncontrollable, so is constantly set at a happy medium. I swapped the older with the newer to test when the two cars were last together, and it worked perfectly in the older (96) car, so the plan was to replace the newer unit, and put the outgoing 97 unit into the older 96 car.

Having hastily bought this replacement, I've re-read the add, which includes both part nos., explaining that one supersedes the other (hence it came up in my search), but it is actually the older of the two. I'll happily keep it to put in the older car (at my father in law's), but won't be able to test it in situ for a few months now, which will be way out of the return period!

This is the replacement part in the newer car, and it's whether or not it will work in the older car without engaging the vent switches, as all the other controls seem to work fine?

​

 

[MD5]

Hi,
I don,t have a 129 but I have a 202 which shared the same climate control unit and I replaced mine for a slightly different part number (same pt no's you quoted I think) with no issues the unit I put in was from a slightly later 202 so I just thought the pt. no. showed it had been superseded, possibly updated software or something to fix the all to common pixelated display which sadly is present on both of mine.
I will check on the EPC for the 202, 129 and the units I have here for pt no's, Based on my experience I would say you shouldn't have no problems.

Hi Andy, and thanks. I think the parts are backwards compatible, but perhaps not the other way round? My newer unit worked fine in the older car, but as the older unit was faulty, I didn't bother trying it the other way around.