neutral shut off switch question

[marc]

Working on the back up lights on the j10-258 which don't work. Since the truck starts, the neutral shut off switch's shut off function is working. BUT does anyone know if the back up light switch function can fail independent of the shut off function of the switch
Thanks, Marc

[Yeller]

Yes it can. I’m assuming it’s an automatic since you have a neutral safety switch, they have separate contacts. But could be other wiring gremlins too, I’d start with with switch, if the light bulbs and sockets are good. The switch can be tested with an ohm meter, either installed or in your hand.

[tgreese]

Which transmission? Have you looked at the TSM?

[Tripwire]

On the 727, the NSS does both the lockout and reverse lights

[marc]

Friends, have been living without backup lights and dealing with more pressing issues with the 84 J10. Revisited the back up light issue. The light circuits are continuous and the shut off function works but the switch is not being activated for the reverse lights. When I got the truck they did not work and it did not start in park more than 30% of the time, my father in law had spent years just whacking the shift lever in a particular way to get it to start? Crawled under the truck and took the slack out of the linkage and it starts and shifts without a problem. Replaced the neutral safety switch to no effect. I am wondering if the generic aftermarket switches have an issue or if the years of abuse might have damaged the part of the transmission that activates the reverse lights?

[tgreese]

Which transmission? It matters.

[marc]

Just to fill in information, I checked the continuity in the neutral safety switch in place, while the starting leg works, the light legs, when in reverse, do not get connected.

[marc]

Regarding which transmission, will check, not sure. I am assuming it is the stock issue as the truck seems very stock.

[tgreese]

Automatic or manual?

[marc]

The J10 is an automatic. As far as I know it has the original automatic transmission, I believe it is a Turboflite 999 I think. As I mentioned, for years, my father-in-law hammered the shifter to get it to start in Park. He routinely brought it to a mechanic who appears to have actually done nothing and then billed him saying that such and such a problem was unfixable? The shift linkage was very loose, just getting the slack out of it resolved the shifting issue. I don't know if the reverse light switch is more sensitive to linkage adjustment than is the shifting process, if so, I might have over adjusted it. BUT, i don't think tha is an issue given it never has shown a reverse light at any point of adjustment.
Thanks, Marc

[tgreese]

Both the neutral safety switch and the backup light switch will be shown on the factory wiring diagram. There is a wiring diagram labeled '84-85 on the Tom COllins site: https://oljeep.com/gw/elec/GW_wiring.html Suggest you read that diagram and find these components. It won't show you the exact location of each, but you should be able to find something familiar on the diagram and follow the wires to the switches.

If the linkage is too sloppy for the NSS to work, you could put a momentary switch on the dash that bypasses the NSS. This could be dangerous, since the bypass would let you start the truck in gear. However, it is a way to get the truck started if you have no other way to do it.

I would do something to fix the sloppy linkage; either make the bushings I needed, have them made, or improvise some replacements. Look at the drawings in the parts book, and at the truck.

If you find the backup light switch, you can short across it and see if your backup lights work. If they do not, you'll need to look at the wiring and the lights themselves.

[marc]

Tim, the odd thing is that the Neutral Safety side of the switch works, can't start it in gear.. It is the reverse light side that doesn't.I replaced the switch, thinking that was the issue with not starting in Park, it wasn't. The linkage was way out of adjustment. taking the slop out of the linkage corrected the not starting in Park issue but the reverse lights still don't work. There is continuity from the switch cap to ground so I will bet the light circuit is intact. When tested with a multimeter, there is no sign of the switch working on the reverse lights. So, either the switches I was sold are defective or the mechanical part in the transmission that pushes the switch has failed. Next step is hunting a schematic of the transmission.
Marc

[tgreese]

Marc, there has to be some position where the reverse switch has continuity. If not, condemn the switch. You should also be able to make the reverse lights work with a jumper at the switch.

Continuity could be a short to ground.

It's a switch, on or off. Not complicated.

[candymancan]

Put 12v at the switch wiring plug to see if the reverse lights come on.

If they do you just bypassed a wiring issue.. and youll know if its the switch or deeper in

[marc]

Resolved the Neutral Shutoff Switch not running the Back up lights. It appears that it has the original cap for the switch which would go on the new switch far enough to engage the shut off but not far enough for the pins for the backup lights. Gently shaved a little bit from the inside of the cap and it snapped completely on the switch and now the lights work.