4430 Netral Safety Switch

Tractor cranks with nss disconnected. I assume someone before has messed with wiring. Can anyone give me any advice on where to start? Thanks!

Check neutral start switch for continuity when trans is in neutral or switch ball is depressed. Sometimes one can remove a sealing washer or 2 on switch then reinstall old switch to gain continuity or remove some slack on shifter mechanism by sliding shifter arm in on shaft.

Don't have any voltage on nss wiring. I assume I should have voltage on wiring when shifter is in neutral. Wiring is disconnected and tractor still cranks. Thanks

(quoted from post at 08:08:48 12/27/18) Don't have any voltage on nss wiring. I assume I should have voltage on wiring when shifter is in neutral. Wiring is disconnected and tractor still cranks. Thanks

Click to expand...

Only time NSS wiring will exhibit voltage is when wiring is intact & jgn switch is turned to start position

(quoted from post at 08:08:48 12/27/18) Don't have any voltage on nss wiring. I assume I should have voltage on wiring when shifter is in neutral. Wiring is disconnected and tractor still cranks. Thanks

Click to expand...

"I assume I should have voltage on wiring when shifter is in neutral."

The only time there is voltage on the neutral start switch wiring is when the key switch is in the "START" position.

The neutral safety switch is connected into the circuit between the key switch and the firewall mounted starter relay.

4630 has a midpoint connector for that circuit just under the floorboards on the right side one foot behind the right battery. Someone could have inserted a jumper here to bypass the nss which is most often gone bad at the terminal connector on it. That bad connector is a double top hat deal that slides onto the switch sideways to both top hats and it's the flat spring component of those spade terminal type nss connectors that goes weak and disallows for enough amperage to operate the starter solenoid with. In order to restore the system you'll have to fix both connectors, midpoint and nss. The top hat deal can be slid apart for this trick by inserting a very thin and skinny sliver of metal (roof flashing, hammered flat) into the connector on the flat side which holds down a flat spring prong that traps the plastic connector to either spade connector. Once apart just insert an automotive pick into the end loop spring to bring back another 40 years of gription to the assembly. nss is midpoint on right side of transmission under a bolt on cover plate in the area of cable workings for shift lever. Just did this two months ago to a 75 4630 powershift. Someone had been in there before since the midpoint connection had been mangled on somewhat.

Thanks for all the info. I'll let you all know what I find!

Not able to find a midpoint connector but traced one side of top hat connector back to the relay and terminall labeled pu in picture. Assume that is correct. Cant understand how tractor cranks with this not bypassed that I can find.

That is correct. But top hat is a two terminal switch and connector, is the other wire missing entirely?

The relay depicted is for dash and accessory supply, it is cut off when starter engages making a sound very similar to starter solenoid but it's location is left side of steering wheel column under the cowling and it operates backwards from what one might assume. It is powered with the same side of START position of key switch, but turns accessories off during cranking.

Previous owner has used this connection (PU) from key switch to starter direct apparently?




Here is AT85153 nss that I'm thinking you have. Two standard spade terminals will go onto those two top hats but they tend to fall off easily without the plastic connector that holds them to prevent that from happening. You could wire from the one without a wire to your starter solenoid and replace and tape up the wire currently there.

Earlier diagrams in this thread show the nss on the left side of transmission up high, perhaps your midpoint connector is also on left side under the floorboards as well?

RE38390 is part number for NSS listed for a 4430.which is located on RH side of trans case. AT85153 isn't listed in 4430 PC.

Thanks for that quick info Tx Jim. I must have been confused with the other nss thread of recent as to location of it. Your number is the one for 4630 too which is the one I was working on and fixed, but both switches have the same dual top hat connector that seems to age poorly and I settled on the first picture of one I could find to steal and post in here. Turns out it's still the only picture of the top hat part I can find. But RH side of trans case is right where the 4630 was too with about three foot of twin wire wiring harness in cloth protector from there on up to the midpoint connector just under the steering wheel cowling. They did have the switch under a bolt on cover where it can't be seen very well, but it is well protected tucked away in there like that. I slid a finger in there and bumped it which allowed it to start again with nothing else done and I already knew about the horrible track record on how this double sideways one off spade connector is always failing to perform when they get long in the tooth. 3020 has this top hat nss too but probably yet another number. It's never the switch, it's the connector that needs slapped up side the head a bit.