2-4 select to j-shift conversion help

Here's the wiring diagrams for 2-4 select and j-shift systems, thanks to @Area51Runner for sending them to me for my swap. You'll need the relay I mentioned above, all the connection terminations can be made in the dash harness. I just cut out all the unused connectors under the truck (6-pin actuator, 4-lo sensor (if you don't have ABS and want e-locker anytime), etc).

I have all the pin/wire connections needed mapped out to work with the relay, let me know if you want them. The only one I had to do separately is the 4wd position sensor, I ran a ground direct to the relay because all of the grounds for the 2-4 select system are tied together, rendering the position switch wiring useless for the j-shift system.

 

Don't even need another position switch, the one on the j-shift case works fine. I actually swapped the one over from my push button case so that the connectors would remain the same, but if you don't mind splicing or wiring a new connector then nothing new is needed on the case itself.

 

Wow, simple enough. So position switch found on the j-shift t-case is the same as the one on the push button case, with a different connector?

 

Correct. The switch from the push button case is slightly different shaped if you compare them side by side, but they’re the same length and both engage with the 2-4 shift rail exactly the same way, which is all that matters.

 

@drr that would be great! I actually tracked down the plugs to make an adapter for that sensor. I'm trying to keep it all plug and play, just incase I ever NEED to go back.

 

@drr I just realized that you're in my area! Let me get the parts together and the first rounds on me for the info!

 

Sure, see attached doc for pin number map and wire colors for the 4wd ECU and Transmission Control Relay. Note that you'll have to add one extra ground wire directly from the 4wd position switch on the t-case to the transmission control relay (pin 7), as the circuit is ground switched and using a common ground won't work (at least I don't think it will). You also need to just splice together pins 21 and 19 from the 4wd ECU, they don't attach to anything else.

Pin numbers for the 4wd ECU:


Pin numbering for the Transmission Control Relay plug:

Sounds good to me!

 

I am not even doing this swap, and I am so appreciative of this information. This is awesome. Thanks a lot man.

 

@drr ,I was just going through your right up and had a few questions. Is this a swap of the 4wd ecm to relay, or am I adding the relay to the wiring? Will this make anything else stop working, because I noticed there's no connection for the speedo being made.

 

Good question, the relay completely replaces the 4wd ECM. The ECM has a lot more functionality than the j-shift setup needs, and does it in a different way.

I was confused about the speedo as well, it is unclear in the EWD how it wires into everything. Turns out, you don’t need to do anything with the speedo, it works independently of the 4wd system. I think the 4wd ECM just has a speedo input so it can limit the e-locker engagement to low speeds (think you have to be under 5mph or something like that).

 

Ok! I was worried I had tracked down and bought some wrong connectors.

 

Also, for anyone looking into this or following, there doesn't seem to be male counterpart for the 26 pin connector. At least not any that are intended for making an adapter pigtail. TE connectivity makes 178762-1, which is the connection on the 4wd ecm. My hands aren't steady enough, so I'm going to have a friend solder the wires and heat shrink everything.

 

I salute your effort to make this a reversible mod, but you’re going to end up with multiple connectors under the truck just hanging out, as well as all the unused pins from the 4wd ECM which includes some 12v power leads. Are you going to keep all that taped up in case you need/want to revert back to the push button case?

 

Yeah. The unused 6 pin actuator plug is packed with dielectric grease and as taped and sealed as I could get it. We're working on the conversion connector today, and we'll figure it out as we go. But thanks for the reminder, I forgot about those 12 volt leads.

 

Ok! Everything is together! The dash light is no longer blinking! And 4wd still isn't working... dammit. Alright, I'll start checking sensors.

@drr that pin 7 to sensor ground, does that replace the sensor ground? Or is it added to the ground circuit?

 

Yes, the sensor ground needs to be wired directly to pin 7 on the transmission control relay, it is a closed circuit (ground switched). It can't be part of the ground circuit, as anything else that is ground switched would close the circuit. That was the only wire I had to run separately from the wiring harness.

 

Ok. Yeah, I need to check if that switch is working then.

 

It should be, if your 4wd dash light is working. The same switch sends power to the light, and switches the relay to send power to the ADD.
If your ADD is not actuating, sounds like it may be a different issue.

 

Light doesn't come on when I shift into 4wd. I knew I should have checked the sensors while the transfer case was on the ground. I'll check the fuse as well. I'm sure it's something simple at this point.

 

Hello there, glad to find this thread. I just finished installing my 4x4 swap on my 04 dbl cab and final piece of the puzzle is the the wiring to the add with the j shift tcase. Do you have a picture of what your harness looks like. I believe I have an idea what it’s suppose to be but I was like to double check that. I have the transmission control relay that ill be using