2005 base 23000 mi

I have a simlar problem with No Start, which I posted before. After reading the threads I removed the control relay module to inspect any fractures in the printed circuit.

I cant find any damage even by using a mag glass.

The car started when it was cold.

Here are the pictures.








MK

 

Even tho you are not seeing any weld fractures the issue maybe with the contacts, dirty or pitted or a coil is breakin down ! I'm not sayin that is definetly the issue, but it is something to consider. Good luck with your quest !

Just my Dos Centavos

 

Stogey, that was my thought as soon as I saw those contact relays. The contacts would be fairly simple to cleanup and see if that fixes the problem. An intermitant coil is a real pain to find.

MikeR

 

Have these poor parts designers never heard the words "hermetically" and "sealed"??? Sometimes German parts manufacturers make me crazy.

German car electronics are like American car interiors - they get them all wrong.

Look at the size of those components. Discrete resistors at 68 ohms as well as a diode all on a single-layer PCB? That thing looks like it was designed in the 1970's!

I'm surprised there aren't any vacuum tubes in these babies.

 

So this means that I have to buy a new control module.

I will.

However, what are the other modules that can go wrong? The one comes to mind is the clutch switch.

Regards

M Khan

 

If you read through all the previous threads on Mistery No Start and Relay Control Module, there are quite a few, I know !!! Try to relate some of the symptoms previously mentioned to the symptoms you are experiencing with your car. That may help your diagnosis.
For instance, mine would start cold and only times when it was hot. When not starting hot and the key was turned to the "ON" position, I didn't hear the fuel pump start up and prime the system as was always normal. Or you could wait till you have a "No Start" condition and "tap" the side of the Relay Control Module containment and see if it starts then.
I hope some of this helps, it can get frustrating as HELL to attempt to trace down minor electrical mishaps !!!
BTW: if it does turn out that the CRM is bad, your local Mercedes dealer should have the part in stock and alot cheaper than if you went thru Chrysler !

Just my Dos Centavos