Testing and expected results:
Test 1: With the cable harness installed behind your push button start and with switch on the new harness in the On position (or bare wires touching from each of the two long wire ends if you haven’t attached your switch yet in order to complete the connection – being careful not to touch anything else while doing this so nothing shorts out) Start the truck as you normally would.
Expected Result: Truck starts as it normally does by either pushing the button or if equipped using remote start on the FOB.
Remote start further step: Once truck is running, enter the truck and push the push button start to remove notice on the dash and have truck continue to run.
Resolve issues: If truck does not start by pressing the push button or pushing the push button start after you remote start your truck and then pushing the push button start does NOT clear the display, check the following
Ensure both new ends of connector is fully seated on both original wiring connector and back of push button start. If that looks good, remove harness and check to ensure you have the metal ends within each new connector fully seated (they click in when fully seated when you assembled them).
Test 2: With the cable harness installed behind your push button start and with switch on the new harness in the Off position (or bare wires NOT touching from each of the two long wire ends if you haven’t attached your switch yet in order to complete the connection – being careful not to touch anything else while doing this so nothing shorts out) Try to Start the truck as you normally would by pressing the push button start.
Expected result: You should NOT be able to start the truck by simply pushing the push button start button.
Remote start further step: Truck WILL remote start using the FOB. Enter the truck and push the push button start to remove notice on the dash. This should NOT work. Once successful either put the switch back to on and push the push button start button again, or connect the wires together if switch is not yet installed.
Resolve issues: If truck did start check switch position or ensure wires are separated (if no switch yet attached to long wire leads on new harness) for new long wire leads on harness. Same thing if you remote start the truck and then push the push button start button and it clears the display notice check the switch to be in off position or wires separated on new long leads in harness.
For this OFF test, you do not need to check the new ends or pins within the new connectors, because for the OFF test to Fail something is making the connection on the switch or new long wire harness connection.
My own testing: Before I went to do this write-up, I did test the harness you see in the pics above and it worked as expected first try. I have not even ordered a switch myself yet, but tested it with the new long wires having bare ends and either connecting them or not depending on the test. And this thing works Great! Having 2ft of wire for the switch part of the harness may be too long for some depending on your location choice for where you hide the switch, but I don’t think would be that much waste to just cut off to length you need when you mount this in your truck. If you really want to put the switch in somewhere like your center console or door even you would have to solder/connect a longer bit of wiring to make that distance. Again, it all depends on where you mount it. I did verify that this harness works with 4th Gen push button start (as I own a 2016 Ram 2500) and I have a 5th Gen Red Ram TRX push button start module I tested it on as well and the new connection ends and wiring are identical to 4th Gen, so will work on newer as well. In fact the 5th Gen Red push button start actually started my 4th Gen just fine! Just the lighted Aux and Run lights on the switch itself didn’t light up – nor could I mount it in the truck as its very different mounting approach. 3D Printer time? Maybe later.