Wiring universal ignition switch to farmall 504 diesel

[down_right]

So I am fixing up the wiring on a farmall 504 diesel. I have replaced the alternator with one of those 63 amp fast start" 1 wire alternators that is internally regulated and doesn't need to be excited or anything, etc. i want to upgrade from the key switch and push button/start setup to just an ignition key switch, but am unsure of how to properly do the wiring with this specific type of alternator

There are 4 terminals on the ignition key switch

1) The raised middle terminal: has markings "ST" which I assume is "START"

Is this what connects to the start terminal on the starter solenoid?

2) BATT Terminal (top)

Is this what connects to the starter at the same post as the positive battery cable?

3) IGN Terminal (bottom left)

I have no idea

4) ACC Terminal (bottom right)

This is what I connect things such as the glow plug to? Or for the light switch, this is what connects to either the INST or BATT terminals on the light switch?

I plan to have a couple of those in-line spade fuse things to replace the OEM fuse holder, where in all of this should I splice then in?

 

[Dieseltech]

You'd be better off leaving it stock and keep the ORIGINAL switches working. I put that same four post switch on my 560D and the STARTER spring loaded side did not always stop when it should, unless you jiggled the key back left a bit. The BAT post is HOT, START is start solenoid engage, IGN and ACC are optional. DO NOT change the glow plug circuit and try to run it through that key switch! My 504D has all the STOCK switches and it's going to stay that way.

 

[used red MN]

Hello DR welcome to YT! Tell me a little history of you and the tractor. How long have you owned it, how do you utilize it? Where you at with this or maybe a better question, is the stock wiring still intact? What about the start button do you feel is substandard telling you the ignition/start combination switch is an upgrade? Answer this and I will be back later to direct you.

 

[Steve@Advance]

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So I am fixing up the wiring on a farmall 504 diesel. I have replaced the alternator with one of those 63 amp fast start" 1 wire alternators that is internally regulated and doesn't need to be excited or anything, etc. i want to upgrade from the key switch and push button/start setup to just an ignition key switch, but am unsure of how to properly do the wiring with this specific type of alternator

There are 4 terminals on the ignition key switch

1) The raised middle terminal: has markings "ST" which I assume is "START"

Is this what connects to the start terminal on the starter solenoid?

2) BATT Terminal (top)

Is this what connects to the starter at the same post as the positive battery cable?

3) IGN Terminal (bottom left)

I have no idea

4) ACC Terminal (bottom right)

This is what I connect things such as the glow plug to? Or for the light switch, this is what connects to either the INST or BATT terminals on the light switch?

I plan to have a couple of those in-line spade fuse things to replace the OEM fuse holder, where in all of this should I splice then in?

That's probably not going to be the best switch for that application.

Here's what happens inside the switch:

With the key slot vertical, everything is off.

One position to the left gives you connection between the BAT and ACC only.

One position to the right gives connection between BAT, ACC, and IGN.

One more to the right spring return gives connection between BAT, ACC, IGN, and START.

If the engine has a run solenoid, it can be connected to the IGN, and the switch will work for a diesel application, but it has no provision for glow plugs. If there is no run solenoid, it will be up to the operator to remember to turn the switch off after shutting down the engine.

Another down side, those are not very high quality switches. They are aftermarket, automotive switches, not well suited for the harsh usage on a working tractor, and are not suited for outdoor exposure.

 

[used red MN]

Hey, hope you didn’t take offense to us questioning your idea. I will help you wire this up any way you like. We are all just striving to make your repair the best possible, one that will serve you well and work reliably.