MOD- Condenser Fan & Compressor working together by adding a relay - PeachParts Mercedes-Benz Forum

ROLLGUY · #1 05-09-2014, 07:33 PM

I have been having overload/fuse burnout problems on my 123 on fuse #8. Since I am running 134a and a Sanden compressor, I have made up a wire harness & relay to bypass the factory fuse for the compressor clutch, and run it and the condenser fan together on it's own separate fused power. The first thing I did was harvest some wiring and relays from a parts car:

I used the relay/wiring with the big red wire, but most any relay and wiring will work. I wanted to use a factory MB relay so I could place it in the same enclosure as the other two:

I made up the harness and wired it up like this:

The big red wire (you can use either of the larger wires if one of them is not red, it does not matter) goes to the terminal in the glow plug relay with a fuse holder wired in:

The large black wire gets wired into the black wire of the condenser fan and the + of the compressor clutch. First photo shows the harvested connector plugged into the factory fan wiring connector, second shows the wiring to the compressor= brown from ground, blue from + fan connection:

The brown wire from the fan and the brown wire to the compressor clutch get connected together and screwed to ground (body):

The existing two wires that went to the compressor clutch gets wired into the smaller of the wires from the harvested wiring and relay:

It is actually quite simple, and seems to work great. No more blown fuse #8, as it is only running the blower fan and a relay coil. I may not have explained it good enough and have no idea how to create a wiring diagram, so please ask any questions....Rich

Thread Tools
Show Printable Version Email this Page
Display Modes
Switch to Linear Mode Switch to Hybrid Mode Threaded Mode