#3 Fuse Blowing Off!!!

My #3 fuse is constantly blowing.

This happens even when the headlight switch is at the right parking lamp position only.

The fuse is connected to the right parking lamp, headlight wiper/washer, right parking light and instrument lights.

Need diagnostic help.....

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Albert
91 300CE

[Benzmac]

The quick way to diagnose this is to unplug one of the consumers at a time and turn on the switch until the fuse is ok. I have a little circuit breaker that I use in conjunction with an amp probe so I don't kill so many fuses.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

I think there is a bad wire creating a short circuit in between the fuse and one or more of the component/s, I unplugged both the right parking lamps units and the headlamp wipe/wash units, the # 3 fuse is still blowing once the light switch is turned to the park lamp position!!!

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Albert
91 300CE

[Benzmac]

Don't forget that it could be the monitoring unit. This is the control unit that is responsible for telling you when there is a bulb out in the car. The unit is under the back section of the fuse box. To access it just unscrew the top of the box and remove it. Unplug the long black control unit and then turn on the lights..

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Thanks for the advice, I finally traced the problem to the headlight washer/wipe system, the wires to the units are badly melted creating shorts. I temporaily disconnected the wash/wipe relay (green) so that the parking lamps would work until new wires can be installed. Is there anything in particular I should be aware of ??

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Albert
91 300CE

[Benzmac]

The washing system for the lights is rarely used. I'd leave them unplugged. If you do want new ones the partshop can help.

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Benzmac:
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM