4WD Swap How To - Wiring 4WD indicator light and A/T P (Neutral) light

This is a quick recap on wiring up your transfer case position indicators to trigger the 4WD indicator light as well as the A/T P indicator light.

BIG KUDOS to @mjhenks for his wiring writeup on the 4WD indicator. Also a shoutout to @mechanicjon and @BartMaster1234 who helped with his efforts.

So you're wrapping up your 2 to 4WD swap on your PreRunner and it's time to wire up your transfer case position switch indicators. @mjhenks outlined how he spliced his transfer case position switches together and ran 2 leads up under the floor shifter and tied into IK3 PIN 9 to activate the 4WD indicator.

I wanted to add a twist to it and have the A/T P indicator light up when the transfer case is in Neutral. Essentially, this is a visual indicator to the driver that hey, the tcase is in Neutral and that means you can roll even if the gear shift is in Park!
Now some model years did not have the A/T P cutout on the temperature gauge. Some did - as to what years, I don't know. It is possible to change the face of the temp gauge (they sell them on ebay), or replace the gauge entirely (also can be found on ebay). This is what I did and I'll include info at the bottom.

So let's take a look -

Here we have the switches I used on the transfer case. At the time, I did not have the part#s for the connectors to the switches and figured I'd improvise. I found a similar switch and ordered 3 of them. The downside (and I didn't realize it at the time) to these switches is the lack of a lead which given the limited space once the transfer case is installed, makes connecting them very difficult.



Now for ID'ing the position switches... on the driver side of the tcase, you have 2 switches. The forward switch is for 4HI. The aft switch is for Neutral. On the passenger side of the transfer case you have 1 switch and it is for 4LO.





Now to the wiring...

*NOTE* If you are not doing the A/T P switch like I did, then you can completely leave it out of the equation and unconnected. It serves no purpose to wire it in with the rest.

I used 16 AWG GXL wiring although 18 AWG GXL would be my first choice. I had a bunch of 16 leftover from another project so why not, right? To start, you'll need to -

• Run a wire to the left lead on the 4HI switch. From there you'll splice into that wire with the left lead coming off the 4LO switch. Next,
• Run a wire to the right lead on the 4HI switch. From there you'll splice into that wire with the right lead coming off the 4HI switch.
• Either the left splice or the right splice will be your ground, you decide.

If you are skipping the Neutral switch run the two extensions you just made into the cabin. If you are going to do the A/T P indicator then run 2 leads off the Neutral position switch and take those into the cabin as well. Go up through the floor shifter where @mjhenks suggested in his thread.

You can only see the wires from the tcase on the passenger floorboard but you get the idea.




Next up remove your glove box completely. From there you will need to remove the 3 10mm bolts which hold the upper half of the glove box to the dash. On the backside of this upper portion of the dash, you'll find IK3 (the large connector), IK2 (the smaller connector closest to the passenger seat) and IK6 which is in the rear. We'll be tapping into IK3 for the 4WD indicator and if you are doing the A/T P indicator then we'll also be tapping into IK2. Let's take a look...

Here we see IK3 on the bottom, IK2 closest to the seat and IK6 in the rear.



Although I cannot stand using them, this time I'll make an exception given the amount of room to work in - so grab a couple of T-taps.

For the 4WD indicator, tap into the DARK GREEN wire on the side of the IK3 connector (IK3 is the large one on the bottom) closest to the door. If you look at the above picuture, its on the opposite side of what you see.

If using the Neutral position switch for the A/T P indicator, then you will be tapping into IK2 and the BLUE wire. Again, on the side closest to the door.





For the ground wire(s) toss a ring connector on them and ground them out. I chose this screw.



Give it a test... Set your parking brake and check 4HI, 4LO and if you did it - Neutral.

Success!





While you're here... might as well change out that glove box bulb



What if you don't have the A/T P & A/T Oil Temp indicators on your temp gauge?

As I mentioned at the start of this, you can replace the face/overlay of your temp gauge or just buy another complete gauge outright. You can find both on ebay. Instead of the overlay, I wanted to replace my temp gauge completely as it was behaving a little wonky. So, I ordered a cluster and swapped the complete temp gauge.

To replace, you'll remove your cluster completely, remove the clear cover piece and flip it over. Look for the 3 screws and remove them. Gently lift up on the speedo face and carefully remove the temp gauge. Replace the face/or gauge and button it back up. You'll also need to add 2 bulbs (my prerunner cluster did not have them). I do not have a part# but if I locate one I will update. Here is another YT vid which really details the entire removal and disassembly of the cluster.




Whether you set up for the A/T P indicator or not, this along with @mjhenks writeup should make this entire cluster business a straight forward job. Congrats on finishing up your swap to 4WD. I never want to pull a transmission again. haha






transfer case connector wiring, 4WD swap wiring, PreRunner conversion wiring, A/T P indicator, A/T Oil Temp indicator

 

NOTE on connectors: For those who are looking for the OEM connectors to connect to the transfer case position switches, here is what I found.

Transfer L4 Position Switch Connector: 90980-11156
Transfer Neutral Position Switch Connector: 90980-10923
Transfer 4WD Position Switch Connector (w/2-4 Selector): 90980-11250
Transfer 4WD Position Switch Connector (wo/2-4 Selector): 90980-11156 (same as L4)

Using the above connectors, you can avoid the limited space issue I ran into and work up a harness using factory connectors and the switches which came with your transfer case.

transfer case connectors, 4WD swap wiring, PreRunner conversion wiring

 

Well done. I did not even know the A/T P indicator existing.

 

Thanks. It's entirely unecessary but I wanted to include that original functionality in my build. Another benefit to swapping that gauge/gauge face is I now have the A/T Oil Temp warning light - WOOHOO!

 

There's a statement. True for both my mod and yours.

Confirmed my 04 does not have that indicator. Any idea what years or combination of drive trains had that?

 

The gauge I replaced mine with came out of a 2001 5VZFE AT 4WD. So I'm guessing here prior to 02 and had to be 4WD (?)