Replacement indicator / wiper stalk issues

[mercedes13156]

Hi. I've just had the pleasure of changing over the indicator / wiper stalk on Mrs 13156's CLK again. It took about an hour and was a very straightforward task. However, it's got automatic wipers and now that the job is complete, everything works fine except the wipers. Press the end and it scooshes and wipes as it should, so there's nothing wrong with the wipers. I stuck it on the diagnostics and you can see everything except the wiper switch operating. It's there, just nothing happening at it.

I replaced the wiper stalk on a previous C Class which had automatic wipers and again, everything worked first time, except the wipers. On the way down to the dealership to tell them it was a dud, the wipers suddenly started working.

Am I correct in thinking that the new switch needs to adapt to the automatic control and that it will eventually start to work like it did the last time? Mrs 13156 is a bit miffed that I appear to have broken her car.

 

[mercedes13156]

Hi. More information. I stuck the diagnostics on it and you can see everything working on screen as you press the various switches. The wash and wipe works so there's no issues with the motor or the electrics to it. There's no change on the diagnostic live data screen when I operate the wipers from position 1 to 2 then 3. Similarly, there are no fault codes being stored and even deleting the codes as a precaution does nothing. There's no way to check the rain sensor, but that was working fine before I swapped the stalk out. Could it be the wiper relay?

 

[brianbrian]

Did the stalk you replaced, have the same part No.

 

[mercedes13156]

Did the stalk you replaced, have the same part No.

Yes! The part numbers are the same. I made that point very clear in the parts department.

I've been pulling relays to see what happens. The two yellow ones are identical (same numbers and pins) and "Q" is for Wipers ON/OFF and "L" is for Speeds 1/2. I swapped them over and neither the washers or the wipers worked. I put them back and the washers worked again but not the wipers.

I put the diagnostics on and there's no faults on the combination switch, just that the S4s5 (Wipe Switch) circuit says "Not operated when I put the wipers on. The S4s4 circuit (Washers) confirm that the washers are working.

I think a new relay might fix this.

 

[mercedes13156]

I found the exact match (Merc Part Nr) on Euro car parts for £8.69. Ordered two.

 

[mercedes13156]

Arrrrrgggghhhhh! The wipers still don't work. Anyone?

 

[LostKiwi]

Have you checked the bonnet switch? Wipers are disabled if the bonnet is open.

 

[mercedes13156]

They won't work if the doors are open either. Neither the washers nor the wipers work if the bonnet is open and I've checked the switch in the diagnostics is reading "Closed". I've also seen some information that alludes to a relay in the rear SAM not working and affecting the wipers. I've got a box of odd relays that I've collected which just happen to match most of the relays in the car. I've swapped out the two in the rear SAM, as well as L and Q in the front SAM. The washers still scoosh water and wipe and the wipers don't work. If I swap L and Q over, nothing works. That makes me think that the original is a dud. I've ordered another relay so that both L and Q are new. Then, if it still doesn't work, I'll get it on STAR.

As an aside, I've found quite a few new sites which match up the codes on the relays with Merc part numbers and model numbers.