I can't get enough of this forum! So many of my questions have already been answered in detail. If I missed this, please just point me in the right direction.

I got my hands on a set of front fog lights for my 240 and am curious how they would have been wired from the factory. I've installed lots of electrical stuff, so wiring the switch up to a relay to power them is no problem.

I just want to mimic the factory layout as closely as possible: relay location, which fuse/where to mount a new fuse, and wiring color. If anyone has documentation or photos of the factory setup, I would appreciate it.

 

I've never seen factory fogs pre-wired on a 240 (but all my 240 experience is late versions, I know the 242 GT had them in the grill). most 740/940 are wired for them.

I would put a weatherproof bosch 'high sensitivity' 20 amp relay under the hood, wire the coil pin 86 to one of the parking lights, wire coil pin 85 to a switch you install in the dash, and the other side of the switch to ground. wire relay pin 30 to a weatherproof fuse holder (15A fuse should be fine for 2 x 55W H3 fogs) to the positive terminal (which is on the left fender, its the flat black plastic box with all the red wires). wire relay pin 87 to both fog lamps, and the other side of both fogs to chassis ground.

by using the parking lights as the trigger, you can run your fogs with the headlights on or off, as long as the parking lights are on, and when the lights are off completely, your fogs are off, so you don't have to switch them off separately

I put Hella MicroDE fogs under hte bumper of my 740, and they work great. I use yellow H3 bulbs in them for that old school euro fog light.

 

Thanks! I wouldn't have thought to use a waterproof relay, but other than that, that is my plan.

When it comes to matching factory wiring color, I tried to track down what was done in the 242 GT. Page 107 of this manual shows driving light wiring. I didn't think driving lights were offered in the US, so is that just a translation issue?

 

well, there's some missing text between where that drawing is split across two pages, but the fact that it mentions "HIGH" suggests to me that those /are/ driving lights, switched on only when the high beams are on. fog lamps are normally only used with low beams.

the master schematics like that show every option, many of which were never in the USA.