Factory rear diff lock not working?

[neixian]

Yesterday I was checking the rear diff lock, not as the manual says, there is not a diff lock indicator on when I turn the diff lock switch on.

I started the engine for sure as it is vacuum operated and the vacuum tank is the same one used by a lot of other staff, such as power steering and brake.

And I shifted to Low 2 as well.

Didn't see the light....

Anyone has the same issue please?

[threedogs]

did you drive the patrol or just sit there ?

[neixian]

I just sit there checking....

[threedogs]

I think you need to be mobile for it to engage, can you hear it moving ?

[menace 2]

hmmmmmmmmm

[neixian]

didn't hear anything. I think if there is a light on the meter cluster, I should be able to see it. Unless the manual says optional...
Will check this afternoon, moving it a bit.

[Winnie]

Drive forwards and backwards a few meters... might need some movement to lock in.

[neixian]

Tried it this morning. There could be no light as mentioned in users manual. Maybe need jack up to turn the wheels.

[huardlc]

hi neixian. if its like a normal 4wd light showing on the dash, you need to get the car moving forward to engage the gear. if you sit there, the ''order'' to lcok in is there but nothing will happen. do you have a gq ti i presume ?

[neixian]

Fixed.

I found where the problem is. The engage solenoid is faulty, no sucking when diff lock switch is on, while the disengage solenoids works fine.

When I bypass the engage solenoid, lock works and indicator is on, as shown in attachment.

Apparently, the engage solenoid is dodgy, that it wouldn't open the valve.

Before I torn them apart (they are expensive and solid!) , I tested them using multimeter, both read 36ohm or so. therefore the circuit is OK.

Then I opened them and did a bit cleaning, swapped the engage and disengage valve rods and springs and now all works.

Both are sucking air in turn when diff lock was switched on and off. (If you don't want to turn your engine on and connect the valve to test, blow through some air to see if it is opened or closed.

Here is the diagram telling you how it works (my poor drawing skills):