W220 2003 Mercedes Has Intermittent Power Issues

[ricooryin357]

Hello all. I am working on my uncle's 2003 Mercedes S430 Base. To give you a background please bear with me as this may be long.

Door latch assembly (Driver door) - I replaced it due to him having to put the window down to open the door from the outside while sitting in the driver's seat. Upon inspection, I was able to determine the vacuum housing was broken at the bottom of the door latch assembly. (Apparently this is a common issue. FYI, if you did not already know, Mercedes uses vacuum to lock/unlock as well as secure lock the door.)

Instrument Cluster - He did not have any display on his information center (mileage, fuel range, errors, etc.). I pulled it out using the keys I had order on Amazon. Search for beler 2PCs Removal Tool Keys fit for Mercedes Benz W220. I disassembled it and replaced 1 transformer and 3 transistors using parts I ordered with the Removal Tool Keys. You can find the how-to YouTube. There is a 5-part video on YouTube to give you an idea.

Electrical Issues - Currently I am attempting to diagnose why the instrument cluster sometimes flickers and turns off, why the low beam headlights are out even though there are good (new) bulbs, why the climate controls display is so dim and/or hard to see, the overhead controls work for the sunroof; however, the lamps overhead do not. I am suspecting the SAM module located under the passenger seat is the culprit; however, I do not have a manual, schematic, and/or diagram to work from. So I will be chasing wires and fuses...

FYI, I am more of a DIY'er than a true mechanic; however, I have worked in the Electronic Communications field since 2001 and in numerous cases had to work on generators for several communication sites. No fun. Any help and/or suggestions is greatly appreciated.

 

[3rixx]

I think you have checked the battery status. When the battery is low, anything can happen. Apart from this, scanning codes in W220 is usually quite useful.

 

[bigchevy66]

There's a lot to unpack here with the various electrical issues, but maybe I can help. While it is entirely possible you are dealing with a single culprit, it is also entirely possible that there are multiple failure points. The 220 chassis was always high maintenance, but especially so as they've aged. I can't tell you how many instrument clusters I replaced at the dealership on these cars due to various failure points.

The headlamps are controlled by opposite front SAM's, and I will try to post a function diagram for how they work. Meaning, one front SAM would not take out both low beams. Do all of the other bulbs in each headlamp work properly? The internal headlamp harnesses always go bad due to heat and age (insulation comes off), so that is normally the culprit for constantly blowing bulbs.

The instrument cluster has a rheostat on it to control dimness/brightness. Is that working properly and does it change any of your climate control dinners?

The overhead control panel has a button to change how the interior lights turn on. Do you have it on the appropriate setting? Are the two bulbs in the overhead control panel blow?

 

[ricooryin357]

Yes there is a lot to unpack. I have not been feeling well so I have not taken a look at the car nor have I been able to respond to everyone. I apologize. I do appreciate all the help. As soon as I feel well enough I will look at the headlamp connections and harnesses.

I did do the following:

On the instrument cluster - I noticed the Dimmer Switch does nothing even after I replaced a transformer and three transistors. I know it is a potentiometer and may have gone bad or something else (if anyone has any suggestion where to start I will greatly appreciate it).

A/C Clutch - It was not working after he had the battery replaced. I verified by observing the clutch not activating upon turning on the A/C to max and turning it off. However, upon using my Launch X431 CRP919XBT to get all the codes, I found that it was put into a "stop" mode and would not engage until I reset the system with aforementioned tool. I checked the A/C High and Low lines with my manifold gauge set. I verified that the pressure/freon levels are within operating specs via WIS. I did find that he may have had/still has a leak due to schrader valve on the low side. I have yet to use my freon sensor tool on the valve stems (schrader valves) to confirm if it is still leaking or not. I don't think it is as like I said before the manifold gauges showed good pressure on the high and low sides.

Climate Controls Display - I have not found in WIS where the display illumination is controlled. Any ideas? I do not want to assume (we know what assume means) the Instrument Cluster controls it; however, I thought/think it does. Again if it is tied to the IC Dimmer switch that would explain a lot. I was think that or the day/night sensor would control it.

Overhead Control Panel - I "calibrated" the sun/moon roof via the control panel and my Launch tool. Error codes for it are gone. The lights appear to be blown. I will have to recheck them as I can not remember from the last time I checked them. Also, IF you are meaning did I make sure the switch for the lights are set to on when door is open or not, yes I made sure to have it set to whenever a door is open they should turn on. I still need to check the bulbs. They could very well be blown.

Rear SAM (Under rear seat) - Okay finally on to this... I found that someone had been in there because the bracket holding the Rear SAM, Tele-Aid Control Module, and another small black box was bent. Two of the bracket screws were bent to the point where the weld gave away... I can see the ground. I plan to silicon the holes and/or adjust them the best I can so they can be reused? (big maybe). I would upload a pic; however, I am having difficulties doing so. Oh well for now. I removed the rear SAM and the tele-aid, opened them up and did not see any liquid damage. I DID notice on the floorboard both where the passenger places their feet (front and rear) and under the rear SAM module is rust stains as well as in one or more of the grommets was some standing water. I am tempted to "bake" the boards for "CYA" / just to make sure there is no water hiding; however, I am not sure if it will help or not. It did/does when I worked on two-way radios (walkie-talkies). Lol.

Airbox (beside Right/Passenger SAM module under the hood) - I lifted the cover to the box and found that the bottom has a large hole beside where the reed valve is supposed to be. I am not sure why someone would do that UNLESS it was the dealership tech when they did "warranty/recall" work? Asking my uncle is not a good idea as he has trouble remember things. He's 80 something now so I try not to make him feel bad.

So as for now I am still digging into how/where the instrument cluster is tied into and/or if there is a common denominator that could cause the fault(s). Again any suggestions and/or help is much appreciated. Thanks!!!

 

[bigchevy66]

I can't remember if the AC dimming is tied into the headlamp switch or the IC dimmer. I would have to dig around in WIS when I had some time.

So is the AC working now that you cleared the fault codes? We used to replace the evaporator temperature sensors on those all of the time under warranty.

Airbox- Yes, it is really common for that rubber restrictor in the box to be removed. They clog up with debris and then flood the interior of the car with water, and I would strongly advise leaving that rubber restrictor out. Yes, they would flood all the way to the rear SAM under the back seat.

 

[ricooryin357]

I have been digging through WIS and I am really new to it so it is taking me a long time to figure the thing out.

AC is working like a champ since clearing the fault codes. My uncle said that when he had the battery replaced he ordered it through MB and then had someone he knew put it in or Advanced Auto/Autozone put it in. Either way that is when the problems started. All the problems... I don't know if that is true or not but I am knocking out the issues biggest to smallest.

Yes I saw that MB had a recall where they had all? W220's needing to get a hole drilled into the bottom/side of the airbox due to the reed valve getting clogged up.

 

[Mersovod]

The instrument cluster is dead. Install a working one from a dismantler and code it.

 

[ricooryin357]

I would agree. However, I have monitored it for over an hour and no change. The display does not go out anymore. I did find a loose connection along the line from the cluster on towards a junction under the flooring. I found a wire corroded as well as some standing water. I have since dried out the flooring and cleaned the contacts. I am tracking down the other issues both with WIS as well as multimeter tests.

 

[ricooryin357]

bigchevy66 I just revisited your post that I am replying to and realize you provided me with a clear cut of the endpoints. Well I wish I would have saved my time digging through WIS to find the same thing you shared. Thank you! A gentleman and scholar. Hats off to you sir. Hats off to you.