Foglight switch wiring

[YNOTBOB2007]

I have a rocker switch with 3 terminals. The middle terminal has the hot from the high beam switch. The top terminal has the wire to the foglight relay and the bottom terminal to ground. When I turn on the foglihts with the switch (high beams on), the foglights turn on but the illuminated rocker switch goes out. When I turn the rocker switch off, the foglihts turn off but the switch illuminates. This is the opposoite of what should happen. I tried swapping the wires on the top and bottom switch terminals but that blows the inline fuse. What am I doing wrong? Thanks in advance!

 

[DirtDonk]

Don’t know the answer offhand, but did you try swapping the top and the middle?
If you’re sure the bottom one is a ground, and it sounds from your testing like it is, then leave that as a ground.

Also, true fog lights should be on with low beams and off with high beams. That’s the law in most states, and that’s where they do the most good anyway.
True fog lights (not driving or pencil beam lights (old term not used much these days)) are meant to have a wide, low cut-off beam that illuminates most below the thickest amount of droplets of moisture in the air. Reflecting back into the driver’s eyes less, and is less annoying to other drivers.
Hi beams can be truly obnoxious in foggy conditions. Hence the need for them on with low beams.

 

[DirtDonk]

In fact, since most switches don’t need a ground, presumably this ground is for rocker illumination only.
Or it’s not actually a ground. It could be another output. But it’s probably for the light.

 

[Oleguy 74]

does the sw have numbers assoated with the terminals.

 

[ntsqd]

I would suggest that the current switch be replaced with one that does not illuminate, and that a separate indicator light be installed.

In CA "Fog" lights can only be on with the low beams; "Driving" lights can only be on with the high beams; but "Auxiliary" lights can be on with either the highs or the lows. Because of this and regardless of lens or light type, ALL of my lights are "Auxiliary" lights.

 

[Oleguy 74]

remove wires from sw.connect ohmmeter to center pin,other lead to bottom pin.turn sw to on.if you have continutypower to center pin ground to top fog lite to bottom pin.

 

[YNOTBOB2007]

remove wires from sw.connect ohmmeter to center pin,other lead to bottom pin.turn sw to on.if you have continutypower to center pin ground to top fog lite to bottom pin.

Thank you. Center pin to bottom pin = 0 off or on. Center pin to top pin = 24 ohms off or on. Does this sound correct?

 

[YNOTBOB2007]

In fact, since most switches don’t need a ground, presumably this ground is for rocker illumination only.
Or it’s not actually a ground. It could be another output. But it’s probably for the light.

Thanks and good to know! but I still have the problem. I only use the foglights offroading to my claim at night....I need them with the high beams...steep narrow road wirth cliffs so I angle them sideways. I don't use them on the highway. These have covers that flip down and I only open them off road. They are 70's japanese Micholettis's.....I guess they were pretty good back in the day. But I don't know the wattage or what size fuse to use. Any suggestions?

 

[YNOTBOB2007]

does the sw have numbers assoated with the terminals.

No. Also, I just switched the middle (power in) and top (power out) and left ground at bottom. No difference, it works but the rocker switch light goes out when the fog lights come on. but it didn't blow a fuse. The only time it bloews a fuse is when the ground is on top and the power out is on bottom.

 

[gnpenning]

Expand your continuity testing on the switch. Check all terminals to each other in all positions.

 

[YNOTBOB2007]

Expand your continuity testing on the switch. Check all terminals to each other in all positions.

top pin to bottom pin = 0 (on or off). I have an identical switch next to it that I swapped and still doesn't work. That switch goes to a rear light. It's wired power in at bottom pin, power out at middle pin, and ground is top pin. So I know the switches are good since they both work when wiring them to the rear light. I must have a gremlin with the foglights. Could the foglight relay have an issue? The relay has 3 wires: the middle wire comes from the solenoid, the side wire comes from the foglight switch and the other side wire goes to the foglights.

 

[YNOTBOB2007]

Expand your continuity testing on the switch. Check all terminals to each other in all positions.

Also, I don't know what size fuse to use. I had 3 amp and that would blow when I switched the wires. So I put in 5. It doesn't blow now but the foglights don't come on when they used to. I don't know the wattage of the lights but they are old and not LED

 

[gnpenning]

You are trusting, I'm a trust but verify person.

You can swap in a know good relay. New doesn't guarantee good. For proper verification you need to know what the terminal numbers are on the relay and where the wires go. You can also test the wires .

 

[ntsqd]

It is very likely that the bulbs in those lights are 55 watts each. 110 watts total; Volts * amps = Watts, so 110/12 = 9.2 amps. They are lights and not a motor (no 'in-rush' current on start-up) so I'd use a 10 amp fuse.

Where, in general, are you located?

 

[DirtDonk]

Got a picture of these lights you can share? Always fun to see cool old school stuff at work.

 

[YNOTBOB2007]

Got a picture of these lights you can share? Always fun to see cool old school stuff at work.

Yes but not sure how to attach them. They are images.

 

[Speedrdr]

Yes but not sure how to attach them. They are images.

Easiest way is to become a contributor for (I think) still only $12/year. The attached photo shows how to become a contributor and add pics thereafter.

 

[SLOWnEASY]

top pin to bottom pin = 0 (on or off). I have an identical switch next to it that I swapped and still doesn't work. That switch goes to a rear light. It's wired power in at bottom pin, power out at middle pin, and ground is top pin. So I know the switches are good since they both work when wiring them to the rear light. I must have a gremlin with the foglights. Could the foglight relay have an issue? The relay has 3 wires: the middle wire comes from the solenoid, the side wire comes from the foglight switch and the other side wire goes to the foglights.

So your working switch has power in at the bottom and out at the middle and ground at the top. Did you try that with the fog lights? When you go battery power to the center and then ground at the top the fuse blows. This tells you it's basically a direct short from center to ground. This could have burned out your new switch because I'm betting the top pin is actually the LED ground.
You should be able to try it with no ground first. Try putting battery power to the bottom pin and fog lights to the center pin and nothing to the top pin and see what happens. If the lights come on then just quickly tap the ground wire to the top pin. Either the LED will light or the fuse will blow.
But on the other hand if nothing happens with center on the bottom and fog on the center and nothing on the top, try using your known good switch to test but again do not hookup the ground. If the lights come on I would replace the burned out switch.