3 Speed Aux Fan drawing
 

Does anyone have a better picture of the modification required to install the ballast resistors on a 1995 W140 3 speed system? I have all the pictures on referenced but cannot make heads or tails of the actual wiring? The picture really does not show the location of where this 3 rd wire goes.

Thanks.

What ultimate goal are you trying to accomplish? Are you trying to improve engine cooling?

My aux fans are not coming on at all. I did use a decade box and was able to get them to turn on in high speed only. There is a black tube style resistor that is located in the front of the aux fans that, from what I have been reading is junk. Most sites suggest removing that resistor and installing the old pre-1994 resistors in its place to correct this issue. There seems to be alot of information but nothing solid on how to wire the resistors in place. The two speed fans is pretty simple and clear cut. But every picture I find of the 3 speed fan wiring has words written in the place that shows the wiring. https://www.k6jrf.com/R15_R151_dwg1.gif . Every place has the exact same drawing - including my All Data Maintenance Manual. The R15 is right over where the wiring is running.

If they aren't turning on at all try starting from the fan and work your way back to find the break down. You know the fans are working. I'm also assuming fuse and relays are working. What about temp sensor? Or have you already narrowed the problem down to the resistors? I'm not too familiar with the 140 set up, but I can't imagine it would be that much different from any other set up. If fans aren't turning on at all there is a breakdown at some point where the signal is being sent to the fan to turn on. Possibly a grounding wire.

*Edit*
See if this link helps: http://www.peachparts.com/shopforum/tech-help/152361-c-low-fan-not-working-w140-m104-1995-s320.html

Thank you! Ended up follow the instructions on that page. All is working as advertised!!

Glad it worked out