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Rain Sensor

15K views 51 replies 10 participants last post by  Deplore 
#1 ·
Hello all,

Vehicle is a '98 E320

Recently, my windshield was cracked. Having purchased a used rain sensor for this very occasion, I told the glass shop to order a windshield with accommodation for a rain sensor, as my 210 wasn't equipped with one. When I initially purchased the rain sensor, I plugged it into the overhead control panel and tested it to see if the system would accept it and if it was actually a good unit. That was a year ago, but I recall it working as it should with a rain sensor. Now, with the new glass and sensor installed, it seems like the system doesn't want to work. I took apart the sensor and confirmed the IR LEDs are working. I now suspect that the computer needs to be informed that the car has a rain sensor equipped.

My question now is, since it is not functioning as having a rain sensor, does that mean I was incorrect when I first tested the rain sensor? I currently have the battery disconnected and the light switch on to hopefully reset the CAN system. If that doesn't work, would the fix just be to have the car coded with STAR? If so, anyone in the Austin area with a STAR system be willing to code my car? I looked into getting a STAR system on eBay and they run around $800, and as a college student that is just not a logical purchase. I'd much rather pay one of y'all for your services.

Any help is appreciated.
 
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#2 ·
I looked into getting a STAR system on eBay and they run around $800, and as a college student that is just not a logical purchase. I'd much rather pay one of y'all for your services.

Any help is appreciated.
Can't help you with rain sensor, but you start your research at wrong place.
Would you read this forum, you'd find that $800 on ebay buys you pirated clone with wormed software, while for less than $200 you can have legal scanner with SD function.
Look under MaxiEcu.
 
#3 · (Edited)
I am not even sure if the rain sensor was offered in 1998 E320. So I do not see how it would work when you first installed it.

edit: I just checked it I see that it was first offered in w210 in 1998. My car does not have it as an option.

The rain sensor lens needs to be installed very carefully with special epoxy to the windscreen, else it will not work. The system relies on the amount of deflected infra-red light and if not installed properly you will have problems.

Second, the way the rain sensor (module B38) works, it is connected to the can bus and communicates with the SAM (signal Acquisition Module) regarding the amount of deflection detected. So, if the rain drops on the windscreen changes the deflection rate to certain extent, the SAM turns on the windscreen wipers till the deflection rate is restored.

For the system to work, the SAM needs to be version coded, and this is done by the HHT tool of the SDS. The rain sensor option must be turned on. Now if you had a replacement SAM with that option turned on (from some other model year maybe). It is possible that the rain sensor future may have worked in the past. If this is the case, and if the rain sensor lens is properly installed, the system should work with the identical windscreen (which has the same thickness and same deflection gradient) replacement.

So I would first check the version coding of the SAM(and possibly the N70, Roof control module where the rain sensor is plugged in) to see if the rain sensor feature is turned on, and take it from there.



Kaj,

I did not know if MaxiECU can do version coding for SAM or any other module.. Does it ?
 
#4 ·
mrboca,

The replacement glass came with the top part of the sensor preglued to the glass. So I think I can rule that out. I am going to try to swap the N70 from my '99 300TD. That way we can see if the coding is in that module or the SAM. If its in the N70 I can just get a "dome light" from the junk yard off a newer car. If it is indeed the SAM then I would likely go the reprogramming route. I'll try swapping the N70 and follow up.
 
#5 ·
Actually I was verifying the N70 version coding but I see that the EIS (N73) has to be version coded , because EIS is the hub for messages.

:::::::
The electronic ignition lock control module (N73) must be version coded.

Possible version coding:

Version
Vehicle version W202/S202/C208/W210/S210
Left hand/right hand steering LHS/RHS
Auxiliary fan A/C system Yes/No
Rain sensor Yes/No
Speed relative wiper control Yes/No
Special vehicles multi-function control module Production, panic alarm/Police, authorities/Taxi with emergency alarm/Taxi without emergency alarm

Multi-function control module, special vehicles Yes/No
Electric seat adjustment, driver's seat with memory Yes/No
Electric seat adjustment, passenger seat with memory Yes/No
::::::
 
#6 ·
So I swapped the overhead control unit from my '99 diesel with a working rain sensor and nothing. So I guess it is a coding issue with either the SAM, the EIS, or both. Now I just need to see if MaxiECU is able to change the coding for those modules.

Damn, and I though past-me was clever buying that sensor just in case.

Also, I used a testlight on the pins coming from the N70, the pin for the black wire had battery positive, the brown wire had ground, and what I'm assuming was the CAN signal wire was positive but less voltage. I don't know much about that kind of stuff, but should I find it odd that the black wire was positive and the brown was negative? I remember messing with other circuits on the car and thought brown was positive.
 
#8 ·
You should have 3 wires coming out from your sensor. Black=positive(switched battery), Brown=ground, and Pink Signal.

The rain sensor does not use the can signaling levels or protocol. It is basically a voltage level which is interpreted and coded in a message sent over to the SAM when the SAM requests it over the can bus.

You can get the EIS and SAM version coding read at a workshop with a scan tool like Snap-On with the right identity key, CarSoft etc, which can interface the 38 pin plug. It would work out cheaper, rather than the dealer SDS option. If the EIS has it version coded, the chances are the SAM has it too, and your problem then would lie somewhere else. If not, I hope a helpful member with an SDS or equivalent, and lives close to you will help you out.

I have a scanner which can read the EIS version coding memory but not able to change it. It is unable to access the SAM because an interface is not available directly from the 38 pin connector.
 
#9 ·
Okay well that means my only option now is to get the modules recoded, since its going to be more of a hassle to swap the SAM and the EIS. The problem is I know of no one with SDS near me. Unless someone actually does lives in Austin, Texas and possesses an SDS, it looks like I'm going to have to buy an alternative. Kajtek suggested the MaxiECU, however I need to make sure it has that functionality. jmn

This is what I was looking at: MaxiECU Mercedes PC Based Diagnostic System 38 Pin Diagnostic Socket - scantool-direct.co.uk
If that can preform SDS level recoding, such as changing settings for the optional equipment (the rain sensor in this case), ECU (speed governor increase), and convince features (courtesy lights, etc.), then I will buy it in a heartbeat.

From Kajtek's previous post regarding purchasing MaxiECU, he provided this list of the MaxiECU's supported vehicles and functions: MAXIECU
Under W210 it has the SAM, EIS, and N70 listed, but I don't know if they're saying it can read trouble codes from those modules, or that it can actually recode and change their settings.
 
#10 ·
When it comes to scanners, there is a distinct difference between a service scanner (like SDS with HHT WIN) and a diagnostic scanner (the rest). With a diagnostic scanner you can peek into the parameters statically and in real-time (if supported) but not set many of them.

For 1998 E320, the 38 pin socket will let the scanners to read the live data from various modules (mainly engine, gearbox, instrument cluster, immobilizer, brake (ASR/BAS), Airbags, Climate Control modules) but NOT from the SAM, door, upper/lower control, PSE modules etc. These functions are simply not available for this model year.

If you check the detailed function support and search for w210, you will see this in the attached.

http://serwer1319334.home.pl/1/maxiecu/en/MERCEDES_ENGLISH.pdf

Also note that the MaxiECU will not read / clear codes from your EGS transmission as it does not support EGS51. It may be a reasonably good tool for newer Mercedes cars where diagnostic support is better.

Interestingly you can get it much cheaper if you want one :)

China Mpm-COM Interface USB with Maxiecu Full Version - China Mpm-COM, Mpm COM.
 
#11 · (Edited)
#12 · (Edited)
You can get the MP-COM hardware from the USA too ($104 bluetooth / wi-fi / usb, all the same price with free shipping. Search for MaxiECU in eBay). I guess you can download the software and pay for the licensing fee for 200 zloty = $48, so it works out something like $150 total without the cable, and then you are all legal and can get the item fast.

I think it would just be a matter of time for China to dish out cracked MaxiEcu software (illegally of course), ONLY IF they see any business case for it. I recently had a quote for a good quality Star C3 hardware, cables, up-to-date software in a hard disk with free DHL shipping for $285. So it all depends what you need it for.

Going back to the question, if the MaxiECU cannot do version coding for various modules (and I believe it will not) the price of MaxiECU is a moot point.
 
#13 ·
I can understand that with cheap labor Chinese can hack $1000 Star scanners, but how much profit they can expect from hacking $100 MaxiEcu?
Polish labor is only slightly higher than Chinese.
Coming to supporting EGS51, I think it would be very easy for Mari, but he sees not much market for it.
Driving cars that are turning 20 yo do have some technological disadvantage.
Still better as my 1998 SL500 is not in ME menu at all.
But I can still use OBD part of ME on any car.
 
#14 ·
It is not only labor but the instant availability of materials and the cost of materials. It does not make sense for any small company to set up a production line for one product which does not sell by the millions, so they get them manufactured in China factories, which can produce these along with many other electronic devices that share many of the same components. The Mpm-com device is not only for MaxiECU software, but can be used by many other software diagnostic packages.

I guess we have digressed enough from the subject of rain sensor:)
 
#15 ·
Don't want to "rain" on your parade, but don't you need to change the switch too?

My W209 isn't same car, but similar era.

It has the rain sensor function. I love it, but living in SoCal I haven't needed it for years. (Until this winter)

But when it finally did rain, it wouldn't work. I finally realized that I had turned it off. Why? Because the turn signal is the Windshield Wiper control stalk. When it is in "sense" position a pointy end is pointing up. When in "off" position, it is a larger flat surface.

After years of no rain but plenty of using turn signals I had turned it off to make my fingers more comfy when using turn signal.

Point being, even if you get the sensor wired and SDS coded, if you can't turn it on...
 
#16 ·
I do not know about the W209, but for 1998 E320, I do not see a separate part number for the combination switch for the rain sensor equipped versions. Admittedly, I only looked at autohausaz. The schematic with rain sensor shows the s4 (combi switch) with 4 selections 0/1/2/3, the "0" being the "OFF" position. Possibly the switch selection is interpreted differently if you have the rain sensor option set in EIS and SAM.
 
#19 ·
I am following this thread avidly. My car does not have the rain sensor option, and up here in the Great Pacific NorthWet, I would dearly like to have it, as the non-rain-sensor system has only ONE intermittent speed, and that's the most ridiculous thing on my car.

If I can merely buy a rain sensor, bond it to the glass, and recode the EIS & SAM using the SDS and multiplexer I already have, that would cheer me greatly.
 
#45 ·
If I can merely buy a rain sensor, bond it to the glass, and recode the EIS & SAM using the SDS and multiplexer I already have, that would cheer me greatly.
I've tried to re-read this thread and self-summarize, but I'm lost.

Sam, can you corroborate/correct this?

To add the rain sensor option to a '98-on W210 that doesn't have it:

  1. Install Rain Sensor (physically plugs into N70, overhead console)
  2. Version code EIS
  3. Version code B38 in the N70

Do I have this right?
 
#20 ·
Having had a 1997 and a 1998 W210, I can settle this question about intermittent wiper/rain sensor.

1997 had no rain sensor, and setting the stalk at "1" from 0/1/2/3 would set it at intermittent wiper, which is to set the wiper to move at every so often, usually X amount of seconds.

1998 has the rain sensor, and setting it at "1" would initially activate the wiper once, but then thereafter won't turn on the wiper until the rain sensor detects water on the windshield.

2 is just constant wiper movement, 3 is fastest movement.

If the rain sensor was coded in EIS, then would make sense that it became an option on the 1998, as thats the year the electronic ignition/key become standard.
 
#26 ·
UPDATE:

I went to the dealer today, and the shop foreman and I attempted to change the settings. We changed the setting in the EIS to tell the car it was equipped with the sensor. However, position one on the stalk just functioned as position two, no rain sensing at all. The N70 I have installed was from '99 and it was good, the EIS was fine too, however we found that the SAM had no option for a rain sensor when we tried to adjust the settings. We looked at the hardware/software date, and it was '96, before they even had rain sensors. So the course of action now is to get a SAM from a junkyard. I just gotta find one from a '98/'99 with a rain sensor. I know some '99s had the electronically controlled engine fan, so I will be avoiding getting a SAM from a car with one of those to avoid throwing a code or something. Are there any other things on the cars that would make it to where I shouldn't get the SAM from them?
 
#27 ·
The SAM part number for your car is 022 545 53 32. From hardware point of view, this part should fit in E320 1998 to 2002, and also fits a host of other Benz's with model tear 1998+. The trick is the programming. Ideally, a part from the same model year with the same features (rain sensor) should fit with no programming, but it could be hard to find it in a JY or Ebay. So likely, some dealer programming will be needed.

I am kind of surprised how a 1996 SAM would work in your 1998 car. Because, there is no SAM in a 1996 E320 :). If I remember correctly, 1996/1997 E320's have CCMs, (Combination Control Module) which were located at the passenger side. The SAM you have probably belonged to some other class Benz.
 
#29 ·
After you installed the rain sensor, to N70, did you reset the N70 ? Typically the modules do not see the configuration changes on-the-fly. The technician should be able to check data for the N70 to see if it is recorded as installed, and if installed he should be able to check the rain sensor data. Maybe the SAM version coding options is depended on the configuration data from N70 during start-up ?
 
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