I have installed the green front fog light switch from a car in the bone yard for my front auxillary fog lights in the blank spot where the other rocker switches go. When I pulled it out, I failed to notice how the lighted portion was wired so when the switch is turned on, it lights up so I know it's on and for night driving. It doesn't seem to me that that little bulb would take a full 12 volts, but again, I could be mistaken. How and where to I wire it to work like I want it to.

Thanks.
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'86 sedan with 335K miles with original engine and automatic transmission

I've read he posts below to date, so this is to smiplify.

The switch should have three prongs. One for power in, one for power out to the fog lights, and one for ground which is for the light.

The light socket has a spade lug for ground and a little metal tab on the side which makes contact inside the switch. The tab is the hot side, coming from the switch and is hot when the switch is closed => fog lights on.

Test by connecting the ground to a ground point, then touching a test lead from the hot side of the battery (I would be doing this beside the battery) to first one and then the other of the two remaining spade lugs. The one that lights the bulb is the one that should go to the fog lights.

Good project,

Bob

:>)

The only wiring diagram I could find that shows fog lights has the light in the switch taking power from #87 of the relay.
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'80 DL 2 door, '89 DL Wagon

Basically yes, the small indicator bulb will run on 12 volts, and should be in parallel with the fog lights the switch is controlling.

I've seen the internal contact where the bulbs slip into the switch. I would think that contact must be switched. If that's the "hot" side of circuit (as in #1 below), then the pigtail wire off the bulb holder goes to ground. But be sure you know which side is hot and which is ground!

Which side is which depends on which way you wired the fog lights:
1) Power goes into switch, then to fog lights, then to ground.
or
2) Power goes to lights, then to switch, and switch sends it to ground (a somewhat less likely arrangement). In this case, hot power goes to the fog lights and also to the indicator light, all these feed their ground side towards the switch, and the switch goes to ground only when you turn it "On".

There's precious little on the car that doesn't run on twelve volts - any different voltage requirement would require its own regulated or somehow different power source. What happens with low-current-usage items like tiny bulbs is, they have a very high resistance which is what keeps their current draw so low. Items that draw lots of current, like heater fans on "high" and starter motors, have very low resistance.
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Sven: '89 245, IPD sways, electric rad. fan conversion, e-codes, 28+ mpg - auto tranny. 850 mi/week commute. '89 245 #2 (wifemobile). '90 244 (spare, runs).