SRT-4 Fog Light Switch Mysteries Revealed

That Damn Fog Light Switch

Every other Dodge I have owned since 1985 with fog lights (and there have been several) has had a switch that was easy to bypass. All you had to do was clip the wire from the headlight feed, jumper it to an ignition-switched source, and voila! I could turn on the fog lights any time the ignition was on, they would stay on with the high beams, and go off when the key was turned off. Perfect.

If you are reading this, you well know that Dodge really went out of their way to make this difficult with the fog light switch in the SRT-4. Read on to find out what they did, and see how to modify it to act properly. ;-)

The Contraption

Here it is, what Dodge calls the Multifunction Switch.

I bought this one (they're about $60), so it doesn't have the wiper control module bolted onto the right side, as it would have if I had taken it out of the car.

I wanted a spare to mess around with and not risk wrecking the one in the car. Good thing, too.

Switch Cap Removal

Getting the cap that controls the lights off was a royal pain. There is a split roll pin holding on the cap (bottom left). You can't see it very easily in the car, as it's on the back side of the cap. You just see a tiny hole with a glint of metal in it.

I really had to hack at the end of the cap to be able to get the pin out. I suppose I could have drilled it out, but as you can see from the hole in the control shaft (top center) there isn't much room for error if you're going to put this back together. I was able to fill the cap in with body filler and paint it so you'd never know it was apart, but now that we know what's going on, you won't have to do this.

June 4th update: Several SRT owners who have done this mod have had good luck drilling the roll pin out. To make this work, you have to start with a drill bit that is just a bit bigger than the hole in the roll pin, so we're talking about small drill bits here. You need to clamp the stalk without gouging it (or hold it really steady) because drill bits this small are really fragile and can break easily. Work slowly and without applying a lot of force. A couple of folks have reported that the roll pin just spun right out and they were able to reuse it. One person ended up drilling the roll pin almost to death, and had to replace it (a good hardware store will have a selection of roll pins). In any case, if you're careful, it is very possible to extract the roll pin without damaging the cap or the stalk.

How It Works

Although it's a little blurry in picture on the left (the picture just above shows it pretty well) there is a grey ring mounted at the top of the control stalk. The bolts holding this on are a very small Torx-head (maybe a T5?), but I found they could be removed with a .050 Allen wrench with a little care.

As the middle picture shows, the grey ring mechanically prevents the fog light switch from being activated while the headlight switch is in the Off or Park positions. The 'ramp' on the ring is what turns off the fog lights when you turn off the headlights. By removing this ring and using a rotary tool to grind off the ramp (right picture), the fog light switch can be activated at any time!

Not Done Yet!

If you were to try the switch at this point, you would be disappointed to find that it still doesn't work. The reason for this can be found in the wiring diagrams in the Service Manual. Not only did Dodge build a mechanical limit into the switch, but they built an electrical one in too.

As it turns out, the dash is wired so that power from the low beams is used to feed the fog lights (yes, really, there is no relay!). So, if the low beams are off, the fogs won't come on, even though we can now activate the switch anytime we want. This is also why the fog lights go off when the high beams come on.

The trick here is to cut the feed wire, and patch it into an ignition-switched power supply. This way, the fogs can be on any time the ignition is on, even if the lights are off, and even when the high beams are on.

Getting Power

Here's a nifty little gizmo that will make a clean tap. It comes just the way you see it (I got it at Autozone for about $4), plugs into an existing fuse opening, then allows the original fuse to be plugged in to protect that circuit, plus another fuse to protect the tapped circuit. I'm using 14ga wire for the tap, since that's what Ma Mopar uses in the original application. Since the original application calls for a 10A fuse, that's what I used. Note that the gizmo is only rated for 10A for the new circuit, and 10A for the circuit it is replacing.

I chose fuse position 7 (Driver's Power Window), since there is a nice, fat, 12ga wire feeding this area of the fuse panel, and this circuit only comes on when the ignition is in the 'Run' position, not when it is in the 'Accessory' position.

Because of the strange way Dodge wired the fog lights, there are now two fuses in the fog light circuit: the one at the tap, and the original one at position 19 in the fuse block. Also note: There is a 40A fuse in the Power Distribution Center under the hood that guards the three circuits on fuses 5 (airbag), 6 (heater), and 7 (windows + our tap). This is one more fuse you could blow if things go wrong on this mod.

The last thing we need to do is send our power into the switch. On the big grey connector, we want to cut the small purple wire with the blue stripe that is next to the pink wire with the green stripe, not the big one. There are two purple wires with blue stripes on this connector. The other (bigger) one feeds the headlights, and you definitely don't want to cut that one!

I actually put connectors on both ends of the cut wire so I could put things back to stock if I wanted.

Installation

With the multifunction switch reassembled, it's time to swap it with the one in the car. The swap is actually not that hard, which is a really welcome surprise, since every other Dodge I have owned required removing the steering wheel to remove any control stalks.

Following the directions in the Factory Service Manual (just gotta have it!), you remove the upper and lower shrouds from around the steering wheel, unplug the connectors on the back, unbolt the unit, and out it comes. You have to disassemble a surprising amount of the dash to get the shrouds off, so if you are doing this without the manual, realize that you have to undo the upper dash pad (screws at each end, pops up), the cluster bezel (pops up), and the lower kick panel (two screws at bottom, swings down, lift up), plus the two screws under the column that hold the two halves of the shroud together.

Since I am changing multifunction switches, I have to transfer over the wiper control stalk to the new one. After doing that, it just bolts in, you snap on the connectors, close up the shrouds, and it's done!

Sign of Success!!

How do you know you've done it right? The dash lights are off, but the fog light indicator is on!!

Final Thoughts

Was it worth it? Sure!! Most of the fog light mods that use a separate switch don't light the dash indicator.

Note that if all you want is for the fog lights to stay on when your high beams are on, you could do just the wiring part of this mod.

A really ambitious person would use the control stalk switch to power a relay that then feeds the fog lights. This might get you a little more brightness, while retaining the dash light (there is no change in brightness with this mod vs. the factory setup). This much was enough for me.

Enjoy!