Good morning,

I am having problems with the 2004 SL500 left rear window does not function locked in the open position, the Trunk assist is not functioning, and the Vario roof is not functioning at all. The Xentry indicates the Central Gateway is communicating with the Can Bus however other related modules are not.
The Electronic Ignition Switch will start the car and allow to shift the transmission in drive but that is not being recognized via the Can Bus.
I started checking all modules for connection corrosion and have not seen any.
The question I have is has anyone ever replaced the 20 + years C1 4700 uF located in the front prefuse block? I look for exact replacement and not come across one . Does anyone know here I can obtain a replacement?
Thanks

 

4700 uF capacitors are common electronic components, available from parts distributors. Please post a picture of the capacitor to show its size and voltage. Are you in the U.S.?

 

Thank you for your reply,
The C1 capacitor is cylindrical aluminum can 30 mm diameter 40 mm length . Manufacturer label on top is "EPCOS" 000 547 22 01 B4 1991-B5478-Q5,07.03.S3 .

I measured the capacitance and rated at 4700 uF and the measured value is 5000 uF no bulges on the can nor lakes.
I googled and E Bayed and found similar sized caps that ranged in price from $3.95 to $148.00 .
I would like to find a suitable replacement that will correctly fit inside the pre-fuse block, otherwise I will place the original back since the rating is close to the expected value.
I just want to get the beautiful 4600-pound paper weight out of garage going again.
Thanks

 

There should be a voltage rating printed on the capacitor, maybe 25V or 50V since the application is 12 volts. The capacitor at https://www.mouser.com/ProductDetail...%252BHrw%3D%3D has suitable ratings. These capacitors do age over time, usually developing leakage that prevents them from holding charge.

 

I'm not sure how we got from trunk, window, and top don't work to replacing a totally unrelated capacitor that tests OK.

Start with the window, all four must work for the top to function. The regulators have German plastic cable pulleys that disintegrate, so that is the most likely. It can also be a bad motor or bad relay in the RVC module.

Also, if the car starts, you at least have CAN-C communication between the EIS, ECU and ESM.

 

Good morning MikeJ65,
Trying to determine why the Can Bus is not communicating Central Gateway with the EIS and other modules related to non-functioning Vario Roof, Trunk assist, Keyless Go and non-functioning left rear window. The car starts and runs smooth, and the instrument cluster is operating without any issues.
Because of the age of the car, I wanted to check as many fuses as possible and control modules and SAMs connectors for corrosion that I can. So far, no connector corrosion has been found. I removed the left rear window assembly from the vehicle and checked the mechanics of it and opened the motor and manually electronically tested and it worked on the bench without any problems.
The capacitor within the pre fuse block is over 20 years old, since electrolytic capacitors do fail over time and not sure if this filter could cause a problem with the Can Bus. Since the fuse block is now opened, I wanted to change out the capacitor as a preventative.
The one problem I did notice and repaired was with the overhead control panel since that was not communicating with Xentry. I removed the OHCP opened the module and noticed a lot of dust around the miniature fan. The miniature thermistor sitting above the fan was caked with dust, so I cleaned it carefully with a Q tip and alcohol. Well, the steel wires attached to the thermistor crumpled due to severe corrosion. I went on Amazon and for $8.00 got 10 new thermistors replaced the broken one and now the fan is working but still not communicating with Can Bus.
The car mechanics and underneath are pristine no corrosion or oxidation as though the car never saw rain. The fuel filter was original and holding bracket looked almost new.
Just trying to find the cause of the non-functioning vario roof and related components, otherwise I will have to get rid of the vehicle.

Any solution that leads to repair the vehicle of the vehicle would greatly be appreciated.

 

It's hard to say what purpose this capacitor has, but presumably it provides some essential function, or it wouldn't be there. For $10, it's not worth pursuing diagnosis. Just replace it and move on to the next troubleshooting step.

 

Yes, the gas cap is very easy and cheap to replace, so I would change that out.
If that doesn’t help, then perhaps the left rear tire valve.

I agree with Mike J65 “I'm not sure how we got from trunk …”

Perhaps try a diagnostic of the CAN network?

 

I replaced a fuse in the rear SAM to get the quarter window to function. I could hear a relay clicking when I activated it's driver's door window switch. The roof will not function without functioning quarter windows.

 

I also previously fixed the rear quarter window IIRC by replacing the roof control module with a used one of the identical part number, and/or the window motor assembly. It sounds like your window motor is working. If it is not binding in the assembly, or after installation, I would again check fuses then consider changing the roof control module.

 

DavidCA,
I am trying to understand why certain MB modules are communicating to my DAS/ Xentry while other components and modules are not . When I look at Quick test results there are no problems with Central Gateway but the left rear window, vario roof and the EIS Can Bus indications are "Communication Error" and all failed at the same time.
I already checked all fuses and all are good . The question I had is when I opened the prefuse blocks to check those fuses and for corrosion on the connectors , which are good, I noticed the original capacitor in the block. After reviewing this and other MB forums I have not seen any post about the C1 capacitor. I do not know its function.
How many SL500 owners ever checked that capacitor to see if its leaking or shorted out which would may affect the signal for the Can Bus or for preventative measure to avoid expensive electrical repair down the road? If this capacitor has no value to the protect the electrical system, why would Mercedes Bens install them in over 100 k vehicles? Can we remove this from the SL 500 so as to no longer worry about them failing?
Also the Overhead control panel while functioning, also has no Can Bus communication. When I removed it from the vehicle, I disassembled it for inspection and found the miniature fan cover with lots of dust and the thermistor steel wires completely corroded. this was a inexpensive but easy repair. I saw 2 you tube videos on this issue but no posts.
About 2 years ago, I had a problem with the right front SAM and after removing it I found small amount of corrosion on only one of the connectors are the bottom of the SAM. I cleaned with contact cleaner and repaired the problem I had.
I am seeking guidance to repair this vehicle.
Like other MB owners, I use this forum to learn more about this beautiful but over engineered vehicle, review other members post with their issues and share my experience on how I made repairs.
That's all.

 

Aega,
Thank you for your reply.
Yes, I checked all fuses, I also got another vario roof control unit and substituted and tried that. I removed all the modules located by the rear SAM fuse box and checked the connectors for corrosion and none found.
All the other windows work and when I try the left rear window switch, I hear a click coming from the right rear compartment but the window will not operate.
I removed the rear left window from the vehicle and removed the motor, cleaned the circuit board; I did not see any problems and also bench tested electronically from the connector and the assembly worked fine. While the whole thing was apart, I cleaned and lubed the regulator cables and pulleys I understand that there is some sort of electrical governor or sensor that have been known to go bad on the circuit board- I may next have to look into getting another motor assembly.
Initially I had a problem putting the regulator back into its well. But while I was re-installing the rear window with the associated rain shield I found a very simple trick to install the regulator with very little effort. In fact, I removed the right rear assembly and cleaned and re-lubed the cables and pulleys for that unit- functions quicker now.
The vario roof and Can Bus issues all happened at same time and looking for the common cause. The vehicle only 56k miles and chassis is very clean and I am just wanting to get it back on the road and keep it for Sunday cruises and car shows.
I do appreciate your posts and if you can think of anything else, please let me know .
Thank you

 

I change my oil before having to scrape it off the bottom of the oil pan with a putty knife.

 

Rad Pro,

Please show us the print out from the DAS Quicktest.
We will guide from there.

 

See my thread:
(10) How do I fix Rear quarter window with Circuit 30 RCP CAN Instrument cluster Fault Codes; B1403-001 B1057-001 B1088-001? | Mercedes-Benz Forum
Found it... fuse number 63, 25 amp for RVC control unit (N52)
That clicking sound is probably one of the 2 window relays in the roof control module complaining that it is not receiving the right input. The roof will not function without both rear quarter windows working.

 

What are you using to look at the modules? You say Xentry, but is it X-Dos or passthrough (VCI)? (pass through uses a simple CANBUS decoder, while X-DOS uses a C3 or C4 multiplexer.

As you know the R230 uses both CANBUS and K-Line for diagnostics (communication) and only X-DOS with a Multiplexer can read the K-Line modules.

If you use a passthrough device to connect you will not see these modules.

New models after about 2005 stopped using K-Line so I believe all R230 need a C3/C4 multiplexer and X-DOS Xentry.