I had to use these to control 5 external devices. The customer brought in the new knee panel with the switches and a big fuse block and wire bundles the dealer sold him. The install for these would have taken a couple of days, it seems. And even then, it would only give 3 external control outputs and switches 4 and 5 did something with the existing lights; not what we needed.
So, I thought I would just use the switch control wires to control the devices but, it wasn't as simple as that. Switches 1-3 provided only 1.7 k ohms to ground and would switch. I reverse engineered the switch panel only to find the switches 4 and 5 were not switching. I found that the switching diodes were open on the panel and had to bypass them to correct the problem. UNLESS YOU ARE A COMPONENT LEVEL TECHNICIAN WITH THE PROPER TOOLS AND SKILLSET, DO NOT ATTEMPT TO WORK WITH THE S172 CIRCUIT BOARD!
I have the schematic for the S172 panel attached along with the external control relays shown on switches 1-3. Switches 4 and 5 would be done the same way but without the external diodes I had to add. Here is the link to download a one page PDF of the schematic from Dropbox, and wiring for the switches to control external devices with a Bosch type relay. USe the password S172 to access the file.
Good luck.
