OM606 OVP fuse frequently blowing
 

Hello

Car is 1994 E 300 Diesel with OM606.910 engine.
One of the fuses on the OVP (overvoltage protection relay) have blown two times today.
The OVP is almost brand new.
The tachometer dies and the electronic idle regulation (ELR) fails.
Can this be caused by faults in the electronic systems supplied by the OVP, for example short circuit in the ELR-control unit?

Or is the most probable culprit the alternator?

Thanks in advance for any advice :)

check for short circuits

Any blink codes present?

Original harness been replaced yet?

Hmm, have not checked....

Funny you should ask...
I just had a look see under the intake manifold and the cable harness is in really bad shape.
The insulation on the wires connected to the ELR-actuator is completely disintegrated.
It will have to be replaced as soon as possible.
Checked EPC and where I live (Norway) the harness will cost 1.150 USD:mad:

>>where I live (Norway) the harness will cost 1.150 USD

I fitted one about this time last year, which cost me just less than £300 in the UK - if it's the same part number, and you know someone who is coming across...

W124E300TD - Sorry to hear about your problems. Although my wiring harness is currently in good condition, I know that it will only be a matter of time before it goes ka-put.
Almost $1,200 sounds like lots of hard earned cash for a harness...can't you find someone to rewire it for less?
I'm sure I read somewhere, either here or over at Benzworld that one of the members is rewiring harnesses and seems to be doing an excellent job.

124 440 4032 is the part number.
It is special for cars with automatic, catalyst and AC/ACC.
Hmm, to check other countries is an idea :-)

Actually, I'm thinking about doing it myself :)
Been doing some more cheking, all the plugs and pins are "cheap" and there are in fact only 11 wires in the main harness from behind the battery to the ELR/EGR sensors and actuators.
How hard can it be? :)

Try this site;

http://www.mercedes-benz-parts.co.uk/

Put an A in front of the part number, and take the spaces out.

I don't know if they'll ship to Norway.

Funniest thing...
As soon as the problems with the OVP-fuse started - it stopped.
There has been no problems during the last 8 months.
Anyway - the harness has got to be replaced.
I have bought 11 different colour wires and all the pins, bushings and plug housings needed from Mercedes-Benz and studied the wiring diagram intensively.
After the vacation, first weekend with bad weather the soldering gun will glow :-)