Engine/Transmission (1994 - 1998) Mystery Switch - Wrong Wire???

[blacksheepdiesel]

I printed out the page from TST with instructions on installing the Mystery Switch and proceeded to follow the directions carefully on my 1996. It doesn't work. Checked and double checked to make sure all connections are good. Definitely have the correctly colored wire as instructions state. But the thing does not work. What does happen when I flip the switch is the "Wait to Start" light comes on! Anybody know of the correct wire color(s) on the '96???



TIA



Trent

 

[Dennis Garrett]

It's a black/orange wire, Pin 54 I think

 

[JohnE]

Someone (electrical engineer) at Dodge decided that two similar but system different wires in the same bundle would not get confused. Yes you got the other orange with black trace wire.



You need to trace the wire from pin B11 on the PCM plug per the TST instructions.



PS

I'm a mechanical engineer. I can cast stones when the electricals miss the boat.

 

[krs]

That's right. In English there are two orange and black wires at that location - use the other one.

 

[blacksheepdiesel]

Thanks guys!

I didn't have time to look for a different wire when it didn't work last week. I guess next time I work on the electrical I'll have to dumb myself down just a little bit and think like the engineers!



Trent

 

[JohnE]

<blockquote>...

I guess next time I work on the electrical I'll have to dumb myself down just a little bit and think like the electrical engineers! </blockquote>



If you got a double throw center off switch you can wire it for 3 way operation. , forced lock, no lock, or auto lock.

You cut the (correct) orange/black wire and connect a wire on each side of the cut. Run the two wires inside to your switch. The wire from the trany goes to the center or common. One side of the switch connects to a ground and the other to the second wire leading back to the PCM.

 

[dalton4]

There are two wires with same coloring as others have reported. I also tapped into the wrong wire on first go-around.

 

[Howard Durand]

The simplest way to make sure you have the right wire is to remove the plug to the PCM and check the pin number.

 

[blacksheepdiesel]

JohnE, Great Tip!!!

Your idea will work perfect for me because, unfortunately, I rarely get to drive this truck, usually only when pulling the 30 ft g/n. The rest of the time an employee drives it. This employee would have no clue if I explained it to her a thousand times. So, I will wire it as you stated, make the switch so I can hide it, and this will work better than I hoped!



Thanks!!!



Trent

 

[Joseph Donnelly]

Push a straight pin through the insulation and alligator clip your mystery switch wire to it. After you find the correct orange/black wire, splice into it permanently.

 

[blacksheepdiesel]

Sorry JohnE!

Didn't intend to slam all engineers, just the particular electrical engineer(s) that messed up in this case.



Trent

 

[JohnE]

Trent

Wasn't offended. I just like to jab at electrical types.

Just as amperage and resistance follow the inverse rule (when one goes up, the other goes down) the same appears true for intelligence & common sense.

All engineers are eligible targets for classic blunders, myself included.

 

[Howard Durand]

I am not an engineer but in all due fairness, there are 15 color codes for wiring listed in the book and there are 60 pins in the PCM.

 

[JBlackwell]

Hey guys, school me about this mystery switch. What does it do exactly? I am dumbfounded on this one.

 

[JBlackwell]

Oh, I know what it is now. I didn;t think anyone did that. My first post on this site, I was asking about it and a couple guys chimed in and said don't do it if I want my transmission to live to see another day.



Can someone give me some details about it like can you be setting at and idle before you take off and flip it on or do you need to be in OD and flip it on. I know if you leave it on and slow down you will have some problems.

 

[Howard Durand]

The so called "Mystery Switch" is really no mystery at all.

As you know, it is used to lock the TC whenever you want it to.

As has been said here before, it can do more damage than good if you use it improperly. Using it for acceleration is not good.



About the only time I use it to lock up the TC is when I need the exhaust brake.

I also use it to unlock the TC at times when egt is getting high and I need more rpm or when the driving speeds are going to be 50 mph or less on a congested two lane road or driving around town.

 

[fox]

I seldom use mine now that I have a modified trans with a tight converter.

Actually I use it as Howard says, unlocked below 50 mph.

I use the Geno's steering wheel comander and love it.



For those who don't know, the wireing is different for the 47RH vs the 47RE.

It will set a code on the re trans trucks if done the old way.