Guide to adding the rain sensor (DIY + STAR)
07-04-2022, 07:29 PM
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Guide to adding the rain sensor (DIY + STAR)
I recently added the rain sensor to my 2005 C55. I've seen some threads on this topic, but none had the complete solution. Here's what I did.
I recently replaced my windshield (required) since it was cracked anyway. I replaced it with the rain sensor windshield lens installed.
All parts are sourced from the wrecking yard, so I don't have part numbers readily available
Parts needed:
- Rain sensor. Pop the cover off from inside, remove the wire connector. There are 4 tabs, 2 on either side, which will let it come off.
- Wire harness (Rain sensor has a 3-wire harness about 10" long that plugs into the overhead console). The stand alone light sensor you're replacing has a 4-wire harness that plugs in God knows where - not the overhead console. I just tucked this out of the way. The new harness you're after is glued to the inside of the headliner, so you will just have to pull it free. You will first have to remove the rearview mirror (just pull down hard) and its mount (I believe 3 T-15 Torx), as well as the overhead console. (Remove the lens, pull back on 2 tabs inside the light housing and pull down).
- Overhead console from car equipped with the rain sensor. I thought I was ok with mine since the new 3-wire harness just plugged in, but no... I got "Light sensor visit shop" errors. In STAR, it showed light sensor OPEN CIRCUIT. There must be missing electronics inside non-rain sensor equipped cars. The one I got was from a CLK with a 209... part number, but it's identical. It's the only one they had with the SOS button (none of the W203's had it). I imagine if you have SOS and replace the console without it, there will probably be errors. Why open another can of worms?
- Now for STAR/DAS (if you have it). There are 3 different modules that need to be coded.
- EZS>Read coding and change if necessary>Wiper System>Rain Sensor: PRESENT
- SAM-F>Read coding and change if necessary>Rain/Light Sensor>Select and adjust...>Combined Version (Hella)
- OCP>Read coding and change if necessary>Windshield version>Blue Glass(PPG) [or whatever tint you have]
When that is complete, there is an automatic fine tuning process in the OCP module:
-OCP>Rain/Light sensor>Parameterization and windshield adaptation [make sure your windshield is clean and just do it. its automatic]
As an added bonus, the sunroof has an automatic force adjustment (also in the OCP module)... Mine kept stopping and reversing when halfway closed unless I held the button.
- OCP>Normalization of the tilting/sliding roof's obstruction sensor. [Another automatic adjustment. It shuts off the force sensor and measure how much force it takes to open and close the roof and stores it. No more reversing on me when closing]
I recently replaced my windshield (required) since it was cracked anyway. I replaced it with the rain sensor windshield lens installed.
All parts are sourced from the wrecking yard, so I don't have part numbers readily available
Parts needed:
- Rain sensor. Pop the cover off from inside, remove the wire connector. There are 4 tabs, 2 on either side, which will let it come off.
- Wire harness (Rain sensor has a 3-wire harness about 10" long that plugs into the overhead console). The stand alone light sensor you're replacing has a 4-wire harness that plugs in God knows where - not the overhead console. I just tucked this out of the way. The new harness you're after is glued to the inside of the headliner, so you will just have to pull it free. You will first have to remove the rearview mirror (just pull down hard) and its mount (I believe 3 T-15 Torx), as well as the overhead console. (Remove the lens, pull back on 2 tabs inside the light housing and pull down).
- Overhead console from car equipped with the rain sensor. I thought I was ok with mine since the new 3-wire harness just plugged in, but no... I got "Light sensor visit shop" errors. In STAR, it showed light sensor OPEN CIRCUIT. There must be missing electronics inside non-rain sensor equipped cars. The one I got was from a CLK with a 209... part number, but it's identical. It's the only one they had with the SOS button (none of the W203's had it). I imagine if you have SOS and replace the console without it, there will probably be errors. Why open another can of worms?
- Now for STAR/DAS (if you have it). There are 3 different modules that need to be coded.
- EZS>Read coding and change if necessary>Wiper System>Rain Sensor: PRESENT
- SAM-F>Read coding and change if necessary>Rain/Light Sensor>Select and adjust...>Combined Version (Hella)
- OCP>Read coding and change if necessary>Windshield version>Blue Glass(PPG) [or whatever tint you have]
When that is complete, there is an automatic fine tuning process in the OCP module:
-OCP>Rain/Light sensor>Parameterization and windshield adaptation [make sure your windshield is clean and just do it. its automatic]
As an added bonus, the sunroof has an automatic force adjustment (also in the OCP module)... Mine kept stopping and reversing when halfway closed unless I held the button.
- OCP>Normalization of the tilting/sliding roof's obstruction sensor. [Another automatic adjustment. It shuts off the force sensor and measure how much force it takes to open and close the roof and stores it. No more reversing on me when closing]
