Planning ahead for warmer weather, want to wire in a switch for this. Seems like the easier wiring is to cut the ground wire on the solenoid, run it in thru one of the customer access wires and switch it to ground inside the cab for 4wd (or not for 2 wd). I only have 1 access wire that doesn’t have a planned use, hoping this is a sound approach. Thoughts welcome.

 

Some people simply unplug the connector to the ESOF solenoid on the passenger fender, others install manual hubs and remove the vacuum lines. I took a different approach a while back and installed a switch as you have described in the ground leg of the circuit. I ran a loop from the spliced ground wire, into the cab, installed a switch and then back to the engine bay. I came in on the passenger side of the cab and behind the glove box.

Here is a link to the thread where I was working through the modification to the ESOF system: 2WD low gear mod how-to video!

Some FTE'rs have mentioned that splicing into the ground wire did not work for them and they had to splice into the red wire. I am going off memory here, but the details are in the thread. I don't understand how the red wire works and the ground wire doesn't as the ground wire is what completes the circuit, but I have no reason to doubt what they have said.

I can tell you with absolute certainty, that splicing a switch into the ground wire worked almost 5 years ago and has been working for the past 5 years. I use this often as we are towing our 5th wheel camper 90% of the time the truck is on the road and having this 2WD low mod makes backing the trailer (or another heavy load) so much easier. It moves the load with confidence and at a slow walking pace which is great for threading the trailer into tights spots or up our driveway.

I hope this helps.

 

Hey Sous,
saw your video some time ago. I have a heavy fifth wheel too, thus the interest. Turns out I may not have a spare customer access wire after all with other plans, so I may follow your same path.