Hilcheyhurst

Hope to find some help with a 1995 e320 Cabriolet. Has an issue where it will not start, not even turn over. Replaced battery, starter, neutral safety switch. It's almost like the alarm system cut-off is activated. I now have to hot wire it under the hood with a wire from the starter to the battery compartment. I have read about wiring harness problems but there are no other electrical issues. anyone see this situation before?

One other thing... This happens after a heavy rain storm but not after a car wash...

Thanks! Scott

RBYCC

Scott

Replaced "safety shift switch"...assume that is the neutral safety switch?

Next link in the chain is the K38 starter interlock relay.
Located behind the instrument cluster.
Pull the cluster and jumper pins 30 and 87 on the relay.
This should bypass the relay.
If it starts then bad relay which you can replace or just leave jumpered.
No start then on to "plan-b"....

Ed A.

Hilcheyhurst

Unfortunately Ed, it's back to the drawing board... boo. Replaced the relay behind instrument panel and still we are having issues.

Ever hear anything about the driver door lock actuator being a problem? Its one of the most used parts on the car and I am wondering if there is a connection to the door lock mechanism and related functions and the no start issue.

Scott

RBYCC

Did you try jumping pins 30 and 87 on the relay ?

Even with a good relay it could mean that it's not getting the signal from the trunk mounted Becker alarm module.

Here is how the starter gets signal to start on that car...
Turn key to starter position. Power from ignition switch to starter interlock relay, then to neutral safety switch, then to starter relay.
Starter interlock relay must get signal from alarm system & power from fuse 5

Jumpering should bypass the alarm module.

Hilcheyhurst

Ed, Thank you. Will go and try as recommended. Much appreciated! Scott

Hilcheyhurst

Ed, thanks again. I did find the Becker alarm module in the trunk and using your instructions we were able to get the car started. Any consequence to permanently removing it aside from not having a functioning alarm system? Much appreciate your help.
Scott

RBYCC

Scott

If you've resolved your starting issues then there is no harm in keeping the Becker alarm disconnected.

Another benefit of disconnecting the Becker is longer battery life especially when the car has been sitting.
The system is a constant drain on the battery which is the reason I disconnected mine !!

Ed A.

Hilcheyhurst

The Becker alarm module mounted in the trunk was the culprit in this no start mystery. Somehow, water has been getting into the trunk area where it is located and the module was filled with water. Case closed.

RBYCC

Don't close the case until you find the source of the water entry...
Probably the trunk seal..
You don't want to rust out the inner sheetmetal !

Now go enjoy it !!

AnthonyCatlett

This same thing has been happening my car. The first culprit was water getting into the passenger side floorboard after a heavy storm and corroding a circuit board that is down there. I wire brushed off the corrosion and my speakers started working and so did the electronic locks. It's been fine for a couple months and yesterday I replaced a vacuum hose and started working on replacing the cabin air filter. I gave up and drove home and when I went back out to my car it didn't start and the security light is blinking but the alarm is not going off. Any suggestions?

JulianMartell

I just had this issue, I de-activated it by inserting my key and opening the doors manually. Same problems no turn over and anti theft came on and blinking lights.

AnthonyCatlett

I swapped out the becker alarm module circuit board with one that I had in a 1993 300 E and the car starts and goes but no speakers or electronic door locks still

RBYCC

Not sure if the 1993 module had the same circuitry as the 1994 and 1995.
Merc added more security features with every model year.
My 1988 had minimal security features only entry protection.
The radio didn't even require a security code

AnthonyCatlett

So is that why the speakers and the door lock issue has always been linked to problems with that alarm under the passenger floorboard? So it looks like I'll have to find one out of a '95. Do you know if the transmissions are compatible? The one in my 1995 doesn't like to go in reverse, it acts weak. On flat ground it will go if I rev the engine. Sometimes though it will all of a sudden engage and then I'm in reverse, which is about one out of every 20 times I try. Thanks.

AnthonyCatlett

Water is still getting inside the cab creating a puddle on the passenger floorboard. I ordered a becker alarm for my 1995 E320 and everything has been fine, but we've been getting some heavy rain and I don't want to be stuck anywhere. I assume the water is coming through the sunroof. Any suggestions?