ABS and Diff Lock Warning lights on...

[Unkredible]

Yes, have tried applying vacuum at the actuator on the rear diff and even tried pressure on the lock side. Nothing seems to move in the actuator, which seems to indicate that it is stuck or bent inside the diff...
Took it to a patch of gravel nearby and tried steering left and right etc but seems stuck solid...
It may be cheaper to source a second hand rear diff than having it repaired?
I might try and drain it, open it up and see if I can find the fault...

[Peter Connan]

Weird.

I would think the guys Tinus use to re-gear the diffs should be able to have a look 2ithout it being too expensive? By now they know those diffs inside out!

[Tinus lotz]

Hello man give me a call let's arrange for Collin to have a look
That will be your best bet. Or even Anthony is closer to you

[Unkredible]

Thanks for all the help and suggestions. I had jacked up a wheel, taken it out of gear, and the wheel wouldn't turn. After much head scratching, I figured out I forgot to take the handbrake off :-) Idiot!!!
Seems the diff lock mechanism is still stuffed, but I can live without it being able to engage for a while...
Now to try and trace the electrical fault again...
Very frustrating..

[Peter Connan]

Just to re-cap, the vacuum system is working correctly (IE you have vacuum (only) at one pipe with the switch off, and only at the other pipe when the switch is turned off, all the above with the engine turned on and the transfer case in low range? And this is at the diff actuator, not the solenoid in the engine bay?

And when you switch it on, the ABS and locker warning lamps flash continuously?

If all the above is true, the problem is not electric/electronic in nature. Then, can be only the mechanism inside the diff, or the vacuum actuator (broken diaphragm or leakage around the seams of the actuator unit).
My next check would be to remove the diff lock warning lamp's sender unit (screwed into the centre of the actuator at the diff) and use the tail of a vernier or a screwdriver to check whether there is any detectable movement of the mechanism when the locker is engaged and dis-engaged.

If there is no movement here, I think the problem pretty much has to be the actuator (because even if the mechanism was stuck, I would still expect a little bit of free play in the lever). So if no movement is detected, I would remove the vacuum hoses and introduce low pressure air at the connection closest to the diff and see whether air leaks out anywhere (either from the switch hole, the other pipe or around the unit).

If there is some movement here, either the sender/switch is faulty (in which case the locker itself would be working, you just wouldn't know it by looking at the dashboard), or there is a problem with the diff's internal mechanism.

[Unkredible]

Thanks Peter,
There is definitely correct vacuum at the actuator with the switch on vs off in Low range. Nothing actually happens at the actuator though, so I assume the mechanism is stuffed. I don't think it is possible to remove the Sender / Switch from the actuator. It has a place to apply a spanner, but I applied quite a lot of force and I can't budge it. Any more and I am sure it will break.
I may just try and find a way to bypass the warning lights and alarm which is driving me mad and leave it like that till I have the time to take the diff apart... :-(

[Peter Connan]

Hmm.
One is definitely supposed to be able to remove that switch.
I wonder if the fact that you can't is an indication of the problem (IE rust)?

[Unkredible]

Managed to get the switch off without breaking anything...
Switch is full of Rust. Have tried cleaning it , but I think it is FUBAR.

switch 4.jpg (37.49 KiB) Viewed 5531 times

switch3.jpg (68.1 KiB) Viewed 5531 times

Found the part on Partsouk - Part No 32005-06J2A
Will try the locak stealers but I suspect I'll have to import it...

[Peter Connan]

Elsewhere on this forum I have read that this is the reverse light switch from the 1400 bakkie...

While you have it off, check if the stuff inside is moving, and maybe apply some Q20?

[Unkredible]

The part is available in SA from Nissan, R840.
Genuine Nissan part is US$21 on Partsouk, but US$20 for shipping so no saving vs Nissan.
The Nissan 1400 bakkie switch looks the same but missing the wiring harness and plugs, will have to join the wires to the existing wiring harness. Costs about R140.
I will test the circuit and the actuator - it does seem to move but a bit sticky - will apply some Q20.
Will start with the R140 part and if it works, great, if not will get the Nissan part...
Will update on results for future reference...