[saleen351]

Hello everybody,
I bought 1995 S320 L US version with some issues. Actually they told me engine was seized and got it at very reasonable price.

Found out that lower engine wiring harness was never replaced. Biodegradable bad wiring. I checked the main engine harness and it seems updated one dated 98.
Anyways i saw an ugly aftermarket switch that turned out direct starter switch. You can turn in ignition with the key but can not crank. This seemed a good news for me considering that engine was seized.

I fixed the lower wiring harness and still not successful to crank the vehicle with the key. Ignition switch seems ok and has enough tension on crank position.

I see that i can use button on remote control and lights are illumination on door handles but power locks are not working. Vacuum soft close doors are working fine. I checked the rear fuse panel and saw number 11 fuse was missing. I put new 20 amp fuse and compartment lights were turned on. I tried to lock the vehicle but no power locks and immediately fuse was blown. When i push lock/unlock button on dashboard it makes a funny steady noise while pushing which seems coming behind passenger airbag.

I tried to scan the car from main port through engine compartment with DAS but it says turn on the ignition even it is ON.

Does number 11 fuse have anything to do with cranking problem or something seperate?

I am open to any suggestions and ideas.

Than You


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[Thom_7]

That fuse is for the vacuum pump under the rear seat; it controls the door locks and soft-close function for the trunk. If it keeps blowing out, it means the pump is bad (had the same thing happen to me).

The soft-close for the door and other functions are on another vacuum pump in the trunk.

Likely doesn't have anything to do with your cranking issues.

 

[Merc-S600]

@;Thom already answers the fuse problem .You mention that they told you that the engine was seized , a seized engine by my books has the cylinders blocked and it won't ever turn over ,that could be part of your problem .
When you turn the key trying to start the engine ,some wires might run hot resulting in burning fuses ,be careful and ad some more info here .
Other then that Congrats on the purchase & I hope it won't cost you to much on top to get her going ,even that I would arange a newer engine straight away ,easy found for your model .:thumbsup:

 

[Jayare]

Have you tried turning the motor over by hand using a breaker bar/socket on the crank bolt? Turn clockwise ONLY when facing the motor from the front.

 

[Merc-S600]

Have you tried turning the motor over by hand using a breaker bar/socket on the crank bolt? Turn clockwise ONLY when facing the motor from the front.

Once we had an old Dodge truck ,2tonner ,the engine seized ,what we did is take the spark plugs out & filled the cylinders with Diesel and oil , let it soak overnight then tow started it with a chain behind another truck ,took a fair few goes before wroom the engine came out of its seizure ,It took a lot of tyre squeaks etc but once we added a bit of weight on the back so the tyres don't slip anymore that was the trick.
His car being an automatic there is a way ,read the manual when you/he can insert gear to try a jumpstart,I think if I remember correctly on the w140's you can jumpstart it when you reach 30 or 40 km/ h ,then shift from N to D and not from P to D due to the reverse gear crossing ,maybe it works out and hasn't seized real bad yet .
The hand cranking didn't work unfortunately on our truck but a good idea Jayare ,it certainly is worst a try .:thumbsup:

 

[Jayare]

I'm only suggesting the OP roll the motor by hand to see if it is indeed seized. It's hard to recall any post here or on the W124 forum where an OP has a seized motor.

 

[saleen351]

Thanks for all the help. I also see that i need to be more specific about the problem.
I worked on the car almost 6 hours today.
Good news is engine is NOT seized.
There are some problems though. First i replaced the fuse again for the power locks pump. I do not know but 20 amp fuse blows right away. I put 30 amp fuse and pumps works fine and door locks also rear trunk latch works too. Fuse does not blow even i tried so many times unlock and lock.
I removed the rear seat and see that somebody already messed with it. I also see that there seems something missing in that area. Please look at the photo. If you guys can compare with yours i really appreciate.

Other problem is engine does not start with the key. As i mentioned i repaired lower wiring harness which has 4 wiring (oil level, oil pressure, alternator and starter). As i search more on this forum, i was able to test the ignition tumbler (switch) which seems ok. I removed the passenger side front airbag and able to access the relay. I checked all the wiring on the 4 point connector. Ground, Hot on ignition pos 2, hot on start, and the brown gray wire which seems signal from some sort of control module. I found on google that it gets signal from rear passenger side trunk are just above the fuse panel. If i am not mistaken this module called Comfort Control module. I removed the module and smelled burnt chip. I was able to access it by removing four small screws. As you see from the photos diode was burnt inside and damaged pretty bad.
Do you guys think that there must be some reason for this?
Also can you guys please tell me what this comfort module controls?
As far as my engine runs when i short pins on the relay, i am very happy so i do not need to replace the engine.
Thank You.










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[thisisntchris87]

If I'm right, this is the module that controls the remote central locking and by looking at the ETM schematic it's connected to the Starter lock-out relay module (K38) by a brown and gray wire. Relay also has 4 wires according to the schematic. Seems like a match so far.

This module is also know as the Infrared Remote Central Locking (RCL) module. In the manuals it uses N54 as the reference number.

So if this module is toast, as it clearly looks like it is, then it would be preventing you from starting. Does your central locking work at all? I ask because the pictures I have of the RCL module look nothing like what you've got. Which confuses me, because there is no comfort module in the starter generator schematic.

 

[saleen351]

If I'm right, this is the module that controls the remote central locking and by looking at the ETM schematic it's connected to the Starter lock-out relay module (K38) by a brown and gray wire. Relay also has 4 wires according to the schematic. Seems like a match so far.

This module is also know as the Infrared Remote Central Locking (RCL) module. In the manuals it uses N54 as the reference number.

So if this module is toast, as it clearly looks like it is, then it would be preventing you from starting. Does your central locking work at all? I ask because the pictures I have of the RCL module look nothing like what you've got. Which confuses me, because there is no comfort module in the starter generator schematic.

Thanks for the info. Thats why i am also confused. I was checking mitchell diagrams last couple of hours and it does not make sense. Today power locks were working fine after i put 30 amp fuse. According to diagrams this comfort module has not anything to do with the starter relay. I need to find exactly what brown/gray stripe wire for. Wiring diagrams says both n54 (rcl control module) and n26 ata module uses the same color wire. Starter lock out relay uses 4 pins only as you mentioned. Ground, ignition 2 hot, start(crank) hot, and signal from ata or rcl.
I need to check tomorrow if those two rcl and ata is also fried because of comfort module.
Also dont forget that lower wiring harness was bad and probably caused this fault.
Also SRS light does not illuminate and i can not diagnose the vehicle from main port (passenger side engine bay).
If you check test connector circuit wiring diagram you see that hot in run position first should illuminate SRS light.
I am expecting somewhere in the car has still short circuit which may still fry the replacement modules.
Who ever invented this soy bean biodegradable wiring on these vehicles was a smart guy that allows us to use all the bad words to him.



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