I'm toying with the idea of replacing the stock sealed beams with some Bosch or Hella H4 units, then using some bulbs with higher wattage high beams (90 or 100 watt)

Anyway, to do this I figure the safest way would be to use relays so I don't fry the wiring or headlight switch.

Now, on to the question....can someone tell me how to remove the headlight switch, and also, which wires on the switch are 12V power TO the switch, and also which wire is the 12V power OUT of the switch to the lights.

Thanks

__________________
2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

1) Disconnect the battery since the switch is always hot.
2) Reconsider why you want to remove the switch, since there's not much space to do any rewiring under the dash.
3) The switch is upstream of the fuses, so it goes: battery - switch - fusebox - lights; or possibly battery - switch - fusebox - switch - fusebox - lights when you're dealing with the fogs.

If you want to install relays for higher power bulbs, I'd recommend leaving the factory wiring more/less intact up to about the headlight. Install a heavy gauge wire from the battery to a switched, fused, relay. Use the factory headlight wire(s) to close/open the relay. Using Hella pin outs: 30 connects to the battery via a new heavy gauge wire, 87 to the new headlight, 86 to the old headlight wire and 85 to ground.

When I swapped US-spec sealed beams for euro-H4's in another car, I basically followed the guidance from the Hella catalog. Hopefully this link works:

http://www.rallylights.com/hella/Relays.aspx

Since each filament (left high, left low, right high, right low) was fused and I had a headlight out warning sensor I went with a 4 relay set up. It's a bit more wiring but also easier to undo and easier to troubleshoot.

Ok, that said, then which wire on the headlight connector is power for the low beam and high beam?

Yes, I'm sure I could pop the connector off and check it with a multi-meter, but it has been raining for the last two days, and I am lazy today!

__________________
2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

Well, since you asked so nicely. Leave the battery connected, put your left foot in a puddle and poke around with a hot switch:

Disclaimer: this is from the FSM, use at your own risk. Disconnect the battery since the switch is hot and the screws aren’t really protected. No guarantee of correct info or wiring colors. Blame the PO if you blow something up, not me.
The connections INSIDE the fusebox vary, so your car may be different. E.g. there are Portuguese, Japanese, French, Aussie, etc variants.
Info from the diagram for an ’81 300D
To remove the switch – Pull – HARD – straight out to remove the cover. (For the unitiated, there are two detents: front fogs, then rear fog position – rear fog not installed in US models)
Unscrew the nut.
The cover may/may not pop off. There are alignment pins for the switch
Remove the knee bolster/cover. The switch should be pushed forward then down.
If you can read the symbols:
30 – fat red wire, ALWAYS hot to battery (and starter switch x 2 and fuse #2)
K30 – grey/red, license plate “input”; FROM fuse 1; MAY be hot at anytime depending on switches
P30 - Green/white, standing light input; FROM starter switch, HOT in OFF/ACC
31 – Brown, ground for rear fog (not used in USA, Speculation: I think this is only for the bulb in the switch)
56 - White/yellow, driving lamp (aka headlights); TO the stalk switch pin 1
57 – (commonly grey, various foreign setups)
58L - Grey/white, parking- tail lamp left; TO fuses 3 and 5
58R – Grey, parking- tail lamp right; TO fuse 1
NSE - Grey/yellow/green, rear fog and fog input; FROM fuse 11 (or maybe 5)
NS - Grey/green/white, rear fog output
N - Grey/green, front fog output; TO pin 1 on the headlight connector(s)
K - Grey/green/purple + grey/purple, instrument lights; TO shifter, license, radio (?), buzzer (?), rheostat
The flasher (on the stalk) also gets into the mix. Pins 1, 2, 3 and 11



On the headlight connector pin 4 is high beam (white or white/blk), pin 3 is low beam (yellow or yellow/black)

that is more than enough to get me into trouble Thanks Yak

__________________
2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)