thelaserguy

96 E300d flashers, turn signals, trunk release and rear window defroster non function
I have a problem that just cropped up.
The turn signals, flashers, rear window defroster and trunk remote release all stopped working at the same time.

A little background:
1) the car's wiring harness was replaced about a year ago
2) I just had the ECU re flashed
3) when I was working on the window regulator I noticed the overhead lights would not come on when the door was opened, finished the regulator and put the door panel back on and dome lights work now.
4) I checked every fuse with a meter and pulled and cleaned them.
5) I did the quickie ECU re-set: turn key to on, push accelerator to floor for 5 seconds, then turn key off but leave in ignition for 2 minutes for ECU to reboot, and I did the disconnect battery cable for 30 minutes and still no joy.

Any idea what the common thread between all these items could be?
Trunk release, flashers, turn signals and rear window defroster.
Getting desperate.

That's about it.
HELP!
Thanks!

blkr230

short ... sounds like you came close on door panel

brakel8

How about some repair history? The body harness never needs to be replaced unless the vehicle was flooded, burnt or bad accident. This info will help with the diagnosis.

thelaserguy

Everywhere I go on MB forums people are saying that there were a few years of wiring with bad insulation, and the wiring harness would have to be replaced. They all stated that it was not a question of IF but WHEN it would have to be replaced.
My MB mechanic replaced my main wiring harness under the hood, when it began to exhibit the symptoms others described indicating the insulation was deteriorating.

I did some troubleshooting this weekend and found that fuse #4 located in the fuse box under the rear seat was causing the car to draw 2.6 amps with the key removed from the ignition and no equipment on.

Removing fuse # 4 in the fuse box under the rear seat dropped the amperage draw to 0.025 amps.

The card that identified fuse usage indicated that the fuse was to the Central Control Unit.

I need to inspect that component and wiring harness next.

Anyone know where the Central Control Unit is located?


Thanks for the inputs.

thelaserguy

As far as I know the car has not been flooded or severely wrecked.

There have been a few issues with fuel hoses, the replacement of the wiring harness, shocks etc. But nothing to get excited about given the age of the car and 166,000 miles on it.

The new problem has caused the blinkers to be inoperable and I need to fix this soon, for safety reasons and to get the car through the safety inspection when that comes due.

Thanks for your inputs.

thelaserguy

I checked the fuse placard again and it was fuse # 3 that caused the amps to drop from 3.85 down to 0.026 when the fuse was pulled.

The exact verbiage on the fuse placard is: "CCU-Central control unit, lights"

It appears that the Central control unit is shorted or the wiring harness.

Does anyone know where the Central control unit is located?