Reverse light switch

[devo]

I would add a spacer but it would be pretty thick.

That is what needs to be done....if it's the correct switch, it shouldn't need a really thick washer, but it does need to be shimmed correctly to work right. BTDT...

Well folks, Mike of 23yrRebuild is correct! I put the switch on the ohm meter while installed in the tranny, backed the switch out by exactly 1/16 inch (1.5mm), put it in reverse, and it works! Thank you Mike. My wallet and I greatly appreciate the help. Mystery solved.

Dean

[23yrRebuild]

Awesome ! ...I wonder how many faulty reverse switches out there could be made to work with the proper washer thickness ? ....I've mentioned this several times over the years on the List and Forum. I'm really glad someone finally got some benefit from this tidbit, Congratulations !
Mike

[JDeatsch]

Since the switch is MADE when reverse is selected one can surmise that the 'lever' in the gearbox is not pressing the switch far enough to MAKE it. Shimming the switch would be counter intuitive.

Wouldn't it?

Jim

[spl310]

Unless I am mistaken, the switch is made to accommodate an over shift scenario so that it won't break if the shift fork hits it a little to hard. That is why it needs to be shimmed with the thicker washer.

[23yrRebuild]

Since the switch is MADE when reverse is selected one can surmise that the 'lever' in the gearbox is not pressing the switch far enough to MAKE it. Shimming the switch would be counter intuitive.

Wouldn't it?

Jim

When the switch plunger is out (normally closed circuit)- light is on, when the plunger is depressed, the circuit is open, and the light is off. Inside the transmission, the plunger is always constantly depressed inward in all forward gears, and thus the circuit is open and the light is "off", ...until reverse is engaged and the spring loaded plunger is allowed to travel outward enough to close the circuit and turn the light on. I figured all this out back in 2006, the same way Dean did. It's the "push-button" switch that is pressed to open a circuit rather than close it, that seems counter intuitive, but sometimes a design has a specific requirement....

Additional input: My 4-speed that I discovered and solved this issue, is a servo style. I just now peeked underneath the 5-speed that I swapped in for my stroker, and it is only using a copper crush gasket and did not require a shim or thick washer. I had checked out the switch operation when it was installed and it wasn't necessary....

[JDeatsch]

Interesting approach then. I wonder why they chose to have tension on the switch constantly instead of the reverse.

I'm sitting corrected.

[Linda]

I never fixed this problem, just unplugged the wires and went on to other issues.
Now perhaps it can be solved. Thanks, Mike!

Linda

[msampsel]

Well, glad to be reminded of the way the switch works, thought it was faulty, it was not.
So soldered a wire to the end, added epoxy for strength (hard to securely solder a wire to the tiny terminal! )
and used a 1/16" thick o-ring and the light was on in all positions????

So I went under and cut the o-ring and tightened the switch down and now on only in reverse!
Another twist in a bizarre design of Nissan's or my ability to get it to work!

Anyway, thanks for the info on continuity in the non-depressed or "maybe slightly depressed" switch position.

[Linda]

Thread revival:
Is there supposed to be an O ring to seal the switch from leaking or does the copper 1/16 crush washer do that ? Does anyone know the hole size of the washer?
I assume the late Warner tranny is similar to the Servo trannys except it has 2 switches
Thx
Linda

[devo]

Thread revival:
Is there supposed to be an O ring to seal the switch from leaking or does the copper 1/16 crush washer do that ? Does anyone know the hole size of the washer?
I assume the late Warner tranny is similar to the Servo trannys except it has 2 switches
Thx
Linda

I didn't use an O-ring or a crush washer. The threads on a late model switch are 14mmX1.5, so thats the hole size. I used a Delrin washer for the spacer, and some thread sealant. Thats it.

[Linda]

Excellent, thank you.

[Acegigurn]

where exactly is the switch located on a 2000 Mine is a 1970.

[devo]

where exactly is the switch located on a 2000 Mine is a 1970.

Got to "Powertrain-- Transmission case--5 speed,U20". Its #11 in the diagram.

http://www.carpartsmanual.com/datsun/sp ... 2000-(u20)

[Acegigurn]

actually found it just before seeing this. But now I see it's not connected to any wires from under the hood. Does anyone know where it's supposed to be connected???

[msampsel]

Though I have a 4 speed, I've never heard of a need for new wiring for a transmission swap, it must be on the passenger side of the transmission case.

And page 137 of this http://www.311s.org/PDFs/U20Eng_TrnServ ... nual40.pdf seems to show it (about 3-4 inches from the seem in the tail shaft and the case).