Recap: Wipers started failing randomly, then randomly working again. Assume it was the motor so I took it out and inspected it. The trim under my windshield leading to collection tray is shot letting water get all over the wiper motor. I open up the motor to find the circuit board is fried.
Ordered a used motor that tested GOOD when 12v applied both by seller and myself.
Installed motor and what do you know, wipers still do not work.

SO I hook the car up to SDS and here is what we are dealing with:













Yes we deleted the fault code and tried 3 times to no avail.

I called up a service tech at mb and gave him the above info and asked if he thought it could be the sam or combo switch.
He said no to combo due to the error given and that the signal is interrupted between the motor and sam not sam and combo switch.
He also doubted it was the front same (as do I) since it looks fine and the fact that the sam can recognize the failure.
He thinks that it is the motor.
Great, so I ask if that is the case how can it be since it tested fine outside of the car? He responds that it could be the Hall sensors within the motor. If they are bad the motor will still work under direct 12v power, but when plugged into the car the SAM won't allow it to run until it gets the hall signal. If it doesn't get the signal it doesn't know where the wipers are.

Seems logical but far fetched considering. Not really sure what to do at this point, I could try getting a replacement motor from the seller first or perhaps clean up the contacts from the connector? I will double check the harness where it connects to the SAM. Fuse 57 is fine, not sure how to tell if the relay is or even which relay is the correct one (owners manual only talks about rear wiper relay for long roofs?)

Ideas?

Thanks.

 

get replacement motor from seller

 

Yes I think this is the logical next step, my luck with used parts varies as do most peoples I'm sure... It's bizarre that when I physically touch 12v to the motor on my kitchen table it works but then when in the car it does not? I guess a 3rd motor will rule it out.

Sorry the post was hastily put together.

The order of events:
1. wipers failing intermittently
2. wipers fail completely
3. check fuse (but not relay can not find)
4. Take to indy, indy hooks up sds states it is motor or Sam, not sure go to dealer
5. Order wiper motor off ebay from reputable seller who has tested it as good.
6. While waiting, take old motor out and inspect.
7. Test with 12V jump pack, barely moving acting erratic something wrong.
8. Open motor up and find water logged circuit board, water still around and corroded chips etc
9. New motor arrives, test with 12v jump pack and actuates noticeably better and smooth as it should, no signs of water or damage (did not open)
10. Install in car turn wipers on, no dice
11. Take motor out, test again, same result still moving smoothly to full extension with wiper assembly connected
12.Re-install, disconnect battery for ~ 1min, still no work.
13. Take back to indy, run SDS again, clear faults FIRST
14. Test, no work, clear faults, test, no work, clear faults, test, no work.
15. Took pictures of the above.


Now that that is sorted out I have one question. If you connect a good working motor to the assembly as I did on a bench, then apply 12v to pin 3 and 4 (1 is blank, 2 is for signal), should the assembly go only one direction max out and stop? Or should it then reverse the motor and rotate the other way (as it does when on the car)?
My thinking is that if the hall sensors are shot on this replacement, my "one way" test may have been a false positive. It only rotated clockwise...
I couldn't get it to go the other direction no matter how I touched the pins...
Sorry for my elementary understanding of electricity.

 

 

So motor #3 did not fix the issue.

The only items that can cause this (interruption) to occur between the Sam and the Motor are:
1. The Fuse (it's good)
2. The Sam (seriously doubt it is shot as it's performing it's job correctly)
3. The motor (After 3, I doubt it.)
4. The harness (unplugged it entirely and visually inspected. looks fine)
5 The Relay (Can't find it. Called MB, looked in data sheet, looked in SDS, WHERE IS IT)

I would like to try the relay next but have no idea where it is. There is no information I can find that tells you where it is. The only reference I can find to a wiper relay is for REAR wiper relay in wagons. Is this the same for both? Can someone identify it in the above photo?

 

Your referring to the white relay closer to the front of the car not the one closer to the firewall in the pic? What all does that relay control? Wipers only? A service tech told me yesterday on the phone there was not a wiper relay only a circuit driver or some such contained within the sam... just want to make sure your positive that white relay in the middle is definitely wiper only relay.

edit: they are really more of a gray color

 

Forgive my ignorance. I was able to get a copy of the wis from a member and i see that m6/1 appears to be a relay? It does show a path to fuse 56 for wiper motor.
I dont really understand wiring diagrams so im not sure how to determine the location of m6/1 but i assume the location you told me is correct. What else does this relay control? Sorry i really am learning though.

 

F56 is fed via relay P, the relay I circled is N which is a circuit 15 relay (switched power), relay P is circuit 15R relay, that is another variant of switched power. (Help from forum member)

So p is the relay closer to the firewall not circled, but it appears to control several other functions besides power to wiper fuse so if it fails there would be other items not functional correct?

So would the item in front of my nose be the sam itself? Internal circuit board failure of some sort? Sorry this is way above my head, perhaps you could state exactly what you think it is?

 

Haha ok well thanks for putting the wind in my sail

 

I thought I would post some more info for anyone else trying to diagnose for what it's worth.



It looks like F33 coming from pre-fusebox is what powers this operation. Leads to Relay P which leads to Fuse 56 and then to M6/1 wiper motor.




Seen in fusebox context, Big connector for F33, fuse 56 right in front of it, Relay P back next to the connector that leads to wiper motor.

Appologies, it looks as if f56 is in the back right corner near relay P in that diagram. Strange because 56 is etched into my sam where f57 (what I highlighted) is located...

 

Since Relay P controls other items that if bad should not work, I was curious what else it controls. I'm using very elementary understanding here so if anyone knows (Pluto) what all is controlled by P that would be sweet (I struggle to ascertain this from the documents I'm still learning how they all correlate).

So far I THINK that P controls N73 or "EIS [EZS] control unit" based on the following diagrams. If there are more items it controls please let me know!

 

I have made an incredible error. One that will blow you out of your computer chair.

I am blind. This entire time I was convinced what I was looking at for the fuse location of f56 was infact f57 (I just went outside to verify after my above post of confusion).





Sure enough (obviously) it was f57 etched into the sam. I went to the correct location f56 in the back right of the sam near relay P to inspect the correct fuse for the first time and nearly passed out immediately:





I will be committing myself later this week for a mental evaluation and vision testing.

Thank You.

 

Haven't you been hunting this problem down since January

 

I'm going to go light myself aflame now

 

I would at least like to include something not included in this thread (I mentioned elsewhere) but The fuse makes perfect sense as a direct side effect of the original motor being water logged.













All thanks to the rubber stripping on the collection tray at the base of the windshield deteriorating from the FL sun! (where I bought car).