Case 580K Neutral start switch

Hi all. New to the site. I have a phase 1 580k backhoe that i'm working on. I'm having trouble getting it to start. I believe it has something to do with the neutral start switch. I've tested the switch to confirm that it is a closed circuit when the machine is in neutral so i feel the switch is working correctly. However, the machine will not start unless you ground the white-red wire that connects to the neutral start switch to the machine (aka bypassing the switch). When grounded, it cranks with no problem so i don't think its a starter issue. I can hold the white-red wire the the transmission hosing around the neutral switch and it will crank, but when hooked to the neutral start switch that is showing a closed circuit, nothing happens. I've bought the service manual and studied the wiring diagrams but i don't see where anything else could affect it. The white-red wire is highlighted in yellow. Just curious if anyone has anyone has had this issue before or has any input to what the problem might be. Thank you in advance for any help.

Welcome to HEF Bfleming89

Sounds like a bad ground point.(corrosion/rust/mouse) Have you confirmed that the ground side of the neutral start switch (black/yellow) has truly a good ground to provide to the starter circuit when the switch closes? Try adding a test jumper from a good ground point to the black/yellow contact on the neutral start switch and see if things work properly then. If so, you have a bad ground connection on the black/yellow circuit, likely where it connects on the chassis.

FYI also the highlighting between schematics prints is on different white/red wires which makes things a little confusing to read. (1st print has highlighted wire 3 up from bottom, the 2nd print has highlighted wire 8 up from bottom)

Check your black/yellow wire on neutral start switch It chassis grounds at mounting bolt for chassis magnetic switch. Clean and check 0 ohms to battery -

The "starter magnetic switch" is a relay.
Located under the fuel filler flap you will see two relays, one for the starter - swap them to see if it fires up.

The white and red wire that you say works goes through the neutral switch that you say works to the black and yellow wire on the switch the black and yellow wire should go to ground/chassis/battery- it does not go through anything else.

Fpgm04, I believe you hit the nail on the head. I was able to remove the side console and find where the black-yellow wire bolts to the chassis along with a few other ground wires and it’s not a pretty site. It was buried in dirt and rust has done some damage. The magnetic chassis switch is shot as well. I guess this explains why none of the lights or gauges work properly. Sorry for the confusion on the wiring diagram. My mistake.

laycobeau, I see what you are saying now. I didn’t realize the black-yellow wire is what actually grounds the switch. I assumed it was grounded by the transmission.

Thanks again for everyone’s input. My grandfather and father used this machine for numerous years in construction and then it was retired to use around the farm. Both have passed now and it has been sitting for a while. Hell of a machine.

Is there a specific way to test a safety neutral switch and what size are these top screws

I ohm’d both terminals to make sure it was 0 while in neutral and open in gear. The top of the post are 1/4” in diameter.

Clean that mess up and I bet a lot of stuff will start working. Good luck

I have a new relay ordered and will update when I get it installed.

I have a Case 580SuperK and a no start off the ignition key. I am replacing the relay to the starter but also must check the neutral safety switch as we had to wiggle the shifter sometimes to get it to start. Now there is a no start even when the shifter is wiggled. But I can not find this neutral safety switch. Where is it located??

Caseman580K

Caseman580superk, I have a super k too and the thing refuses to start with the key as well. It actually was a bit intermittent at some point, but mostly wont start from key. The previous owner wired up a separate two wires to the ether start button, and that is used to start the machine every time. I was thinking it was the ignition, but idk. Dont have time at the moment to diagnose, so let me know what you figure out with yours.

Check #32 for function.

Outdoort,
Tinkerer helped me out by sending a diagram showing where the neutral start switch is located on my 580 Super K. You can access this switch by lifting the floor cover which exposes the top part of the reverser. It is identified as Item 44 and listed as #19832. However there are (2) neutral safety start switches on mine and they are mounted off 90 deg fittings which are mounted above the forward-neutral-reverse spool which is activated by the steering column mounted shifter. Now I have to find out why there are (2) where the diagram shows only one and has no 90 deg fittings shown.

The engine start circuit has the key switch which sends 12volts to the start relay when turned to "start". This start relay is located under the Instrument side panel located on the right fender. It closes and sends 12 volts to the starter solenoid. The negative side of the starter solenoid goes out to the neutral start switch and if the reverser selector handle is in the "neutral" position this switch is closed and it connects to an equipment ground and the starter solenoid is activated causing the starter motor to run and start the backhoe engine.

I now have to test the continuity of these neutral start switches to determine if they make contact (closed) when the shifter is in the neutral position. In the past we had to wiggle the shift handle in order to get it to respond to the key start. It now does not respond to anything. In my case I have already replaced the start relay as I found it severely corroded and have cleaned up and reattached the ground connections.

Tinkerer- can you tell me why I have two (2) neutral start switches (Item # 44) mounted to 90 deg fittings where your diagram has only (1) and no fitting indicated???

Caseman580SuperK

The neutral start switch is item #44 which is a mechanical switch.
If you have switches mounted to 90 degree fittings, these are pressure switches & likely for back up alarm operation...... why you have two is the question.
Can you post a picture of your set-up?

As mentioned earlier the starter relay is one of two relays located under the hood release flap on the RHS.
They are likely covered in muck & not easily visible.

Tinkerer and Airman- I have removed the (2) switches from above the reverser control spool (spool moves forward and back via the shifter handle control) at the top of the reverser. They were about 3" apart in a horizontal position and were threaded into 90 deg ells which entered the reverser spool chamber from above and are indeed pressure switches. On the bench test neither one did produced a closed contact ( showed no continuity on the meter when connected to the pins for the wire connections and when the internal rubber seal was depressed). I am assuming that both are defective. It is my guess at this point that the first one is the neutral safety switch in the start circuit and the second is the safety switch for the reverse motion and activates the warning beeping horn when the backhoe is in the reverse mode.

I am now seeking a supplier for these switches and they have only a slight identification as "38S" stamped on the side of the switch body and have 2 pins for wire connections and have a 1/4" male connection for threading into the hydraulic 90 deg ells.

Can anyone provide a supplier reference for these pressure switches????

Call Dale Wiess.
He is retired Case dealer still selling OEM, NOS and aftermarket parts. He is a human encyclopedia of anything related to Case equipment.
Go here ---> http://e-backhoeparts.com/

The CNH part number for the reverse alarm switch is D139904.
The neutral start switch CANNOT be a pressure switch - as you need the engine running to have system pressure to operate the switch.
Item #44 in the above diagram posted by @Tinkerer is the neutral start switch - it is mechanically operated - as shown in post #8 by @Bfleming89 (Part #1983241C1)