Push button ignition

[Peterjk]

RE: I've only got four wires coming out the back of my ignition switch.



So do I on my Thomas. The 4 wires are like in my picture ^^^
1. Batt-12v which is the incoming hot wire
2. ST - start solenoid
3. ACC
4. IGN

[AXett]

I assume the IGN pin is the "pre-ignition" key position, just before turning it over with that ST pin going hot? (As opposed to ACC, which is the non-warming accessory mode)

[Peterjk]

No idea, maybe someone else can answer that one.

[Peterjk]

Here's the finished product. The 5 1/2 inch reclaimed baseboard wood trim helped remove the plastic flexing which was annoying every-time I pulled the air brake knob. I used large screws to trill into the plastic to bind it all together. Flex is gone, everything feels solid. This adds a touch of class to the drivers area w wood trim, and looks nice, I think. Total price, zero $. Thank you all for helping out with the wiring!

[Rock-N-Ruth]

Originally Posted by Peterjk

Hey everyone,
I'm looking to eliminate my 2005 Thomas standard key ignition and replace it w this push button ignition.
The Thmas key is nearly flat, so that would not prevent anyone from stealing the bus anyway, and I have other ways to prevent bus theft anyway.

Has anyone done this?
I dont know if the enclosed relay is needed, Im guessing the ignition already has one?
In theory, when I flip the Red switch On, that would like placing the ignition into Acc more, then just hit the button to engage the started .



Any help would be appreciated.

Your keyed ignition switch serves more than one purpose. It turns on and off accessories as well as the ignition system. It also energizes the glow plugs and last but not least the starter. As long as your replacement switch system covers these bases and is suitably sized, it will work.
You could even design some security into the system if you like.

[Clouse House]

I did a push button on a 84' F-150 a couple years back.
Purchased a start button w/ switch panel. The panel had switches for ignition and accessory. Moved all the wiring from the original ignition switch to the start button switch panel, except for the main 12v wire.
I purchased a "brass ignition switch" from autozone, about $12. It was over by the relays and came with a couple keys. I mounted the ignition switch hidden up under the dash. I took the main 12v off of the original ignition and attached it to the 12v terminal on the new hidden switch. Then had a wire going from the ignition terminal on the hidden switch going to the 12v power terminal on the start button w/ switch panel.
That way with the key inserted in the hidden ignition switch, in the running position, the start button and switch panel had power. Turn the hidden ignition switch to the off position and remove the key, and the start button and switch panel did not have power.
If it was parked at my house or somewhere I trusted like work I'd leave that hidden key in. But if I went somewhere I didn't trust, like an unfamiliar town I'd take the hidden key out and then the truck wouldn't start.

[Peterjk]

My security system is to simply lock the rear window, which disables the ignition.
That feature came with the bus.
Funny story, when i first got my bus delivered, i didn't know about the door and window locks also disable the ignition. First night i locked the side doors and back window. Several days later i tried starting the bus. Of course nothing happened . In a panic, i tried to retrace my steps trying to figure out what i may have done to have caused this. I googled this forum, and discovered the built in feature.
But your general thief that might gain access into the bus probably wont figure out to open the back window latch first.
Having said that, I'm still going to drop in a hidden kill switch somewhere in addition.

[Truthseeker4449]

That dashboard looks nice, too nice, now you're going have to do the rest of it xD

[Peterjk]

I think the starter button went bad but im not sure how to troubleshoot that. When starting the bus at first everything works fine. However when the bus runs for a while, say 20 minutes , after shutting down the bus, it wont restart.
At first, i had to hold the start button in for about 20 seconds, it started that way twice. On the third try it wont.
I have already replaced the starter relay with a exact same Cummins relay, 100a and 400a surge.
Im thinking ill put the old key ignition back in and retest.
Only thing i can think of is that for the push button, i didn't install the included relay. Because the ignition already had one for the key ignition. Could that have broken the push button switch, not using their included relay?
I already ordered a replacement, should be here tomorrow.
Any thoughts im overlooking would be appreciated.
The pics show rhe working switch, the new starter relay and the bus ignitio relay which came with the bus.

[magnakansas]

I have a way to test the switch

7852077600

william

[Peterjk]

Quick update.
Just for fun, after your oxidization advice. I cleaned the contacts on the starter solenoid, wire brush to shiny metal.
Replaced the solenoid even w another new one. Tried jumping both big terminals w a screwdriver, got spark and no starter sound at all.
Next going under the bus w the one hot wire...

[Peterjk]

I dropped the bus off at my local diesel repair shop for a starter replacementz.
Thanks William!
Peter