How To: Replace Your OEM Fog Light Switch with an OTRATTW Switch

battery-fuse-pin 86 (coil)- pin 85 (from coil)- switch pin - led - switch pin - ground. Where does the .01 from the LED change the voltage?

 

You cannot simply put the LED in series with the coil and expect it to light up. The led is only rated for 20mA or so .. the amount of current needed to make the relay closed is probably closer to 250mA. if you were to remove the current limiting resistor in series with the LED then you would put too much current through the LED and blow it up.

 

I believe the OTRATTW switches use "12v" LEDs, which I believe means they have resistors built in

 

Seems like a lot of work when you can just buy the correct switch from OTRATTW. Just need to call them and ask for it. I don't see it on their website but I have it and it works perfectly with no modding.

 

How do you have the upper independent led wired to work?

 

You need to buy an OTRATTW sp switch with an upper and lower independent led. Right now you guys have a standard sp switch with an independent lower light and a dependent upper.

 

but how'd you wire the switch. I understand which switch you got.

 

You need one like this: Upper and lower independent leds. You guys do not have this switch.

 

Yes, I understand. Which wires did you put where?

 

Pin 2 - fog ground black/white
Pin 3 - outgoing to fog relay blue

10- pos illum
9 - neg illum

8 - pos illum
7 - neg jump from pin 3 (so it lights up when in "on" position)


Don't quote me on the colors of pin 2 and 3. I just took those colors from the diagram on the 1st page.

 

How does that work with the illum dimmed?

 

The bottom will dim with your dash lights, the upper will illuminate when on. I can't remember if the dash dimmer is on the positive or negative. If it's dimming on the negative then the top light will be full brightness when on. I have mine non dimmable on the top, so my top is either off or on. The bottom led dims with dash lights.

 

The dimmer works off both neg and pos, that's why I was wondering. I know a lot of people have issues hooking up lights because of this and the leds will dim backwards from the rest of the dash lol.

 

No, one of those wires is the dimming wire. They are both on the same circuit but I believe it's the negative that actually dims it. You use the positive illum wire so it comes on with your dash lights. By jumping the wire 7 from 3 you are getting a non dimmable ground to the led when the switch is on. (if the dimmer is on the neg)

 

I have all of my switches hooked up with upper and lower independent leds and never saw any dim backwards before.

 

It works off of a rheostat, both pos and ground are changed. You must have just gotten the right combination. I am just telling you what I have seen from other people.

 

I'm pretty sure I checked the two illum wires with a multimeter. The top led in a normal sp switch doesn't use the pos from the illum curcuit anyway, only the ground.

 

Exactly. The internal LED which already has a resistor inline is paralleled when the switch is actuated, so it'll illuminate when grounded.

 

Your are correct. dimmer is controlled by the green/white wire which is a ground. If u wanted to dim the upper led as well u need to rewire the harness to send a positive signal to the switch and then jump the green and white wire on the standard switch on 7&8 pin. Then make sure the original hot wire on the fog relay is switch to a ground.

 

not meaning to resurect this thread but if you want both upper and lower to dim just put jumpers on 8 to 10 and 2 to 7 and just hook up other 4 factory wires as normal and they both dim even at the same time man there is sure alot of time spent on wiring these switches looks like a few years lol