After reading about 20 incomplete/dead/unhelpful threads about the CDL wiring I'm still lost.
I've got an 03 (production date 1/03) non CDL Case obviously. I swapped in an 04 case. I've got two switch ports near the CDL actuator. The guy I got the case from was nice enough to give me one CDL lock switch. It looks like this on the electrical side:

I've got nothing like that in my truck to hook that to. As I understand the 04 had two plugs for two switches like these to plug into. I'm assuming one for each switch.
The only extra plugs I see are these female flat single pin connectors. They are green and black wires.



I've read so many conflicting threads as to what these are. Some say they are temp wires. Some say those are what I need to wire these switches to. Other threads have a reference to a certain connector that I need to wire these into.

Can anyone in plain English just tell me where they hooked up thier wires to make the lights on the dash/audibles work? I realize that different years will have different harnesses. There has to be someone else with an 03 that has run into this.

 

The two black terminals = for optional temp sensor in the TC, it's in series with the Transmission temp sensor. I haven't had to do an 03 to 04 swap in a long long time, but I'm pretty sure I remember using the wiring harness from the 04 and installing it into the 03 as the 03 didn't have the connections for the CDL position switch. You'll have N position switch, Interlock Solenoid switch (03/04 is on the shifter linkage itself vs 99-02 where it was mounted on the TC itself), and the CDL position switch if I'm not mistaken.

 

Yes that's true. I don't have the option of an 04 harness at the moment. I'll look for one. Gotta be a way to make it work

 

I put a '99 in my '03. Those two flat connectors are definitely for a temperature sensor, or the left side of the t-case. They probably won't reach over to where the interlock and lock sensor switches are.
My memory of exactly how I wired mine is a little vague, but I do recall that the harness in the '03 is missing a pin on one side of a connector in the vicinity of the gearshift. I forget which one, but if you look at both sides of the connector you'll be able to see that the plug has an extra wire going to it than the socket has (or maybe the other way around). I also had to run a wire to ground for some reason. The '04 is going to be a little more complicated because of the twin switch setup.
I'll see if I can go back through some of my notes from when I did this last summer and see if I can come up with anything more helpful.

 

Thank you. I appreciate that.

From what I read the 03/04 SLABS unit requires no further modification to run the CDL. Whereas the earlier D2s require a SLABS upgrade. I'm not entirely sure what's supposed to happen to ABS/Hill Decent/Traction control once the CDL is engaged. I don't remember what happened when I used it in my previous 04s. But I assume the SLBS unit gets that indication from these lock switches. For that reason I feel like getting this right is really important. I want it to operate as close to factory (2004) as possible.

Right now my interior is a mess w the center console/cover plate out and I'm hesitant to put it back together until I figure this out.

 

Okay, here we go. I found these in a document about swapping just the front output section.



I grounded mine to one of the screws that I used for the transmission tunnel cover plate.

Then all you do is crimp a female spade connector to the end of each of the two new wires (one grounded, and one spliced) and attach them to the terminals on the CDL detect switch.
As far as the SLABS goes, you should be fine with the one you already have. I switched mine to the 2004 SLABS because I had one handy, having previously used it in my '99 truck.

 

THANK YOU. Basically as I see it the switch essentially is a switchable ground to the black/blue wire?

 

Yes, you are feeding ground to the SLABS through the diff lock switch in the transfer case. The issue you have, and are already aware of, is that the 03 did hot have wires coming up from the TC case subharness in connector C0681. The wires ARE present in connector C0668, which is the truck-side of the harness. As mentioned, Pin 7 is the BU (Black/Blue). You want to feed a surrogate ground signal to one side of the switch in the TC and then connect the other side of the switch to the BU wire on C0668. When you lock the diff the switch will close and ground will pass through it and on to the SLABS via your added wiring.

 

Thank you both. This has been extremely helpful. I have one last issue w this.
To verify actuation I hooked up my multimeter to the outputs of switch to check continuity. It seems when I rotate the CDL actuator I only briefly hear the beep of the meter. How long should the switch provide ground? Indefinitely when CDL is actuated? I guess I need to figure out where actuation actually is. It seems to only hit continuity in between being engaged or not.

 

Pretty sure it's supposed to be a continuous connection when engaged. You might want to check on how far in you have screwed the switch. I remember reading something about them needing a spacer washer in some applications. Or maybe yours isn't screwing in far enough.