300 SDL

Has anyone located a rocker switch that will fit in one of the two snap out blanks between the seat heater rockers? I was going to buy a seat heater rocker to activate the two aux. rear lights I've added to my bumper but a Dodge mechanic informed me that it most likely would not work. It would be nice to retain a factory appearing dash if possible.

Ray Roton

Did he say WHY he thinks it would not work?

Peterbilt

If you can find a wiring diagram, you can see how the switch operates. This might provide some information. I'd like to use the switches myself.

Pete

Tfeore

Someone has done this already, used a seat heat switch (I think) and rubbed off the paint. It looked good!! If I find I'll post link...
Tom

gsbrockman

I doubt that switch would carry the amperage of the lights. If it were me, I'd run some heavier gauge wiring to the rear and energize a relay from the reverse lights, unless you need them at times other than when in reverse.
Greg

Jeff in TD

From what I can tell, the heated seat switch is a momentary type, which sends a signal to the heated seat module...

300 SDL

Treore - Please let me know if you find the link.

Ray - He didn't have a complete "why" answer.

Jeff - Maybe that's why.

maynard3 - With a relay even high amps devices only require 14 ga. wire and an amp or so to trigger the device. A 10-12 ga. wire is run from the battery to the relay for power.

Pbilt - I still have to buy a shop manual.

Many thanks to everyone for the responses.

Ray Roton

If it is momentary, that would explain why.
As for the current, that would not be a problem. You would want to use a relay anyway.

Jeff in TD

It's 3:30 am here, and as I was lying in bed trying to sleep, I realized that if the heated switch is a two way momentary type switch, it could still be used to turn on and off backup lights, or whatever else.

You would need two relays, the first one with one set of contacts that are normally closed (ON) and the second one with two sets of contacts that are both normally open (OFF). The common wire for the seat switch would go to negative.

Positive from whatever source would be wired to one side of the contacts of the first relay (normally on) and to one side of the relay’s magnetic coil. The other side of the contacts would go to supply positive to the second relay. The other side of the magnetic coil would be wired to the heated switch’s LOW contact.

The positive wire coming from the first relay would go to one side of the second relay’s magnetic coil. The other side of the coil would be wired to the top (HIGH) contact from the heated seat switch, and also to one side of the first set of contacts of the second relay. The other side of this first set of contacts would go to ground (negative). The second set of contacts would have positive supply from the first relay on one side, and the load (positive side of backup lights) on the other.

This way when you hit the HIGH button on the heated seat switch, you will momentarily complete the circuit to the magnetic coil on relay #2, turning both of it’s sets of contacts on. One set completes the circuit to the backup lights, and the other completes the circuit to relay#2’s coil once you let off the momentary switch (so it basically holds its self on).

When you hit the LOW button, it completes the circuit to the coil on relay #1, which breaks the positive circuit to Relay #2, it’s coil and to the backup lights. Once the contacts of Relay #2 are open (off) Relay #2 would no longer hold its self open, so the lights would stay off once you let off the LOW button…

I hope I explained this correctly. It would be easier in person, or to do a diagram…

Of course, this assumes that the switch is a two way momentary design. I know it has a 6 way plug, but have yet to find a good description of the switch.

Jeff

Jeff in TD

Nevermind...

After all that, I finally found a good description of the switch...

It is a bi-directional momentary switch, with backlight and two LEDs, but it is resistor multiplexed.

Continuity between pins 4 and 6 is 2.2 k ohms in neutral, .415 k for low, and 33 ohms for high.

Aside from surgery on the switch, I don't see how it could work.

Sorry to waste your time reading the above.

Now perhaps I can go to sleep

300 SDL

Jeff,

It's good to know I am not the only one to do this crazy sort of thing in the middle of a sleep period.

Thanks for explanation #2. I guess that's why the mech said it wouldn't work. Guess I'll install that 3 pole micro switch in the blank rocker space. I hit it with 355 degree silver bearing solder and shrink tube yesterday. It's good to go.