Hello MB friends
This is a long one, sorry.
My car, an S210 E300TD, 1998, has suddenly decided that it does not want to turn on the rear dome light, and the light in luggage compartment, when the tailgate is opened. The problem occurred suddenly, without any prior notice or indication of any problems.
I live in Europe, so obviously the car has Euro-specs.
I have now spent several whole days trying to troubleshoot the problem, without success.
The first thing I did was to check all fuses, no fuses blown. The next thing checked were plugs and connections on various devices like rear door switches, shutting assistent module including the micro-switches inside the locking mechanism in the tailgate, the PSE and SAM module under the rear seat. Everything in order with no visible defects, nor are there any signs of moisture or corrotion inside the modules, or anything that suggests that there ever was. I have measured the current to and from the various modules, as directed in WIS, and nothing, apparently, do anything wrong. The next step was to replace the PSE module A37 as several forums refers to this as one of the most likely causes of error, for issues with central-locking systems and interior lights, again without any success since the new (used) module has exactly the same bug, no interior lighting when tailgate is open . I realize that it can be risky to replace with used devices, but the probability of the second PSE module should have exactly the same issue like the original one, is very unlikely, or what?
Another suspect I have in this regard, is that the fault might lie in the electronics inside the shutting assistent unit itself, but the shutting assistent works flawlessly, and I do not really want to spend a pyle of cash, just to find out that the old unit worked fine. I have had the micro-swicthes out of the lock and connected them directly on the wires in the tailgate, brown/yellow and brown, without success, and I have of course checked for resistence in wires and defective switches, nothing. I have ohmed wires from the PSE A37 to tailgate unit, to the rear interior lights, for various chassis mass points to check for broken, cracked or disconnection of cables, yet everything seems to be as it should be.
And it's the most interresting issue of all. EVERYTHING works as it should. Power-lock, remote controls, power windows, both manually and by remote, interior lights when the rest of the doors is opened, and it shuts off as it should do, with delay. I can manually turn on and off the cabin lights, both front and rear, with the controlles in the ceiling or with remote control. The only thing I have noticed is that the car apparently can't detect when the tailgate is open. It flashes 3 times when locked, tailgate open or closed, and the re-lock function works perfectly even if the tailgate is open. But open doors are recorded through the door contacts, so it's probably not that surprising.
The only thing I can think of is that the fault may lie in the rear SAM, but again, what is the probability for that this module wouldt have ONLY one defect, wouldn't there be other issues that could indicate that this device was defective?
Another thing is the upper light controle module N70, behind the mirror. But if I read my wiring diagram correctly, this unit only have 2 Can-connections, can-H, can-L, to the PSE module A37, via a Can-Bus connection, X30 / 7, through the N72 "Steuergerät Unteres-Bedien-Feld", but I suspect that these units are working corretly, because I can measure 12 volts on the light units in the trunk when they are off, and less than 1 volt when power is on, tailgate open or closed. And again, if there was fault in the Can-Bus system,wouldn't there be other indications of this?
There are not retrofitted equipment of any kind in the car, either original or non-original (except for an Alpine radio), and the car is not even equipped with things like electric seats, sunroof or ambient-lighting packages. The car is (unfortunately) quite "low-spec" which (thankfully) helps to eliminate many possible faults, (and less things to breake down) The only unit that has been replaced recently is the EZS/EIS, but it was done by the local Mercedes stealer (not cheap), they could just as well point a gun at me and ask for my money, same feeling.
I often read about problems with interior lighting that does not turn off, power-locks without function caused by interiorlight problems, alarms going off due to Interior lighting, or interior lighting that does not work at all, often caused by defect door contacts, and/ or a faulty PSE. But I have not yet found a single post that describes the same problem as mine, which apparently, (unfortunately), makes my car unique.
The next step is that I will burn the car to the ground, and piss in the ashes ...... joke ...... maybe:angel.
No really, I hope that there are some of you nice people inhere who have an idea of the problem, because my OCD forbids me to ignore this problem.
This is a long one, sorry.
My car, an S210 E300TD, 1998, has suddenly decided that it does not want to turn on the rear dome light, and the light in luggage compartment, when the tailgate is opened. The problem occurred suddenly, without any prior notice or indication of any problems.
I live in Europe, so obviously the car has Euro-specs.
I have now spent several whole days trying to troubleshoot the problem, without success.
The first thing I did was to check all fuses, no fuses blown. The next thing checked were plugs and connections on various devices like rear door switches, shutting assistent module including the micro-switches inside the locking mechanism in the tailgate, the PSE and SAM module under the rear seat. Everything in order with no visible defects, nor are there any signs of moisture or corrotion inside the modules, or anything that suggests that there ever was. I have measured the current to and from the various modules, as directed in WIS, and nothing, apparently, do anything wrong. The next step was to replace the PSE module A37 as several forums refers to this as one of the most likely causes of error, for issues with central-locking systems and interior lights, again without any success since the new (used) module has exactly the same bug, no interior lighting when tailgate is open . I realize that it can be risky to replace with used devices, but the probability of the second PSE module should have exactly the same issue like the original one, is very unlikely, or what?
Another suspect I have in this regard, is that the fault might lie in the electronics inside the shutting assistent unit itself, but the shutting assistent works flawlessly, and I do not really want to spend a pyle of cash, just to find out that the old unit worked fine. I have had the micro-swicthes out of the lock and connected them directly on the wires in the tailgate, brown/yellow and brown, without success, and I have of course checked for resistence in wires and defective switches, nothing. I have ohmed wires from the PSE A37 to tailgate unit, to the rear interior lights, for various chassis mass points to check for broken, cracked or disconnection of cables, yet everything seems to be as it should be.
And it's the most interresting issue of all. EVERYTHING works as it should. Power-lock, remote controls, power windows, both manually and by remote, interior lights when the rest of the doors is opened, and it shuts off as it should do, with delay. I can manually turn on and off the cabin lights, both front and rear, with the controlles in the ceiling or with remote control. The only thing I have noticed is that the car apparently can't detect when the tailgate is open. It flashes 3 times when locked, tailgate open or closed, and the re-lock function works perfectly even if the tailgate is open. But open doors are recorded through the door contacts, so it's probably not that surprising.
The only thing I can think of is that the fault may lie in the rear SAM, but again, what is the probability for that this module wouldt have ONLY one defect, wouldn't there be other issues that could indicate that this device was defective?
Another thing is the upper light controle module N70, behind the mirror. But if I read my wiring diagram correctly, this unit only have 2 Can-connections, can-H, can-L, to the PSE module A37, via a Can-Bus connection, X30 / 7, through the N72 "Steuergerät Unteres-Bedien-Feld", but I suspect that these units are working corretly, because I can measure 12 volts on the light units in the trunk when they are off, and less than 1 volt when power is on, tailgate open or closed. And again, if there was fault in the Can-Bus system,wouldn't there be other indications of this?
There are not retrofitted equipment of any kind in the car, either original or non-original (except for an Alpine radio), and the car is not even equipped with things like electric seats, sunroof or ambient-lighting packages. The car is (unfortunately) quite "low-spec" which (thankfully) helps to eliminate many possible faults, (and less things to breake down) The only unit that has been replaced recently is the EZS/EIS, but it was done by the local Mercedes stealer (not cheap), they could just as well point a gun at me and ask for my money, same feeling.
I often read about problems with interior lighting that does not turn off, power-locks without function caused by interiorlight problems, alarms going off due to Interior lighting, or interior lighting that does not work at all, often caused by defect door contacts, and/ or a faulty PSE. But I have not yet found a single post that describes the same problem as mine, which apparently, (unfortunately), makes my car unique.
The next step is that I will burn the car to the ground, and piss in the ashes ...... joke ...... maybe:angel.
No really, I hope that there are some of you nice people inhere who have an idea of the problem, because my OCD forbids me to ignore this problem.