Difflocks not working

[Roger Crocker]

Hi
After taking my recently acquired 1992 80 off road for the first time recently, to check the lockers, found neither were working, I suspect that they have never been used in anger.
Having no knowledge of these trucks, Where do I start?

 

[Chris]

Firstly Roger it is very unusual, not impossible, but very unusual for this to be an electrical system fault. It's usually a mechanical issue with the locker actuator. Sometimes you can free them up and sometimes you have to take a hammer to them and smash them into tiny pieces to get them off.

But first things first as we've been caught out before. Do you know how to engage the lockers? Don't mean to insult you, but we have spent ages trying to fix people's lockers when they actually didn't know how to engage them and in fact they were working perfectly. What symptoms are you getting?

 

[Roger Crocker]

Ok, had the vehicle stuck in a bomb hole, using low box, turned das switch to select rear diff only, no warning light on the dash came on, despite both showing on start up, tried turning switch to front as well but nothing, returned selector to neutral tried again, turned the engine off the on again, reselected as before but the only light showing was the centre diff warning light.
Much embarrassed at having to be towed by my friends Syncro
I am used to running lockers on my Syncro but they are vacuum assisted, and much easier to get to the actuators if there is a problem.

 

[Chris]

That would indicate an issue with the centre diff lock then I'd think. The front and rears only come live when the centre is locked. Unless you do the mod with the plug that we'll get to another day. It could be as simple as the plug to the diff lock not being connected. We've had that before. Some people like to disable the centre locker for manoeuvring caravans and so on. The CDL is electrically fired unlike some vehicles where it's mechanical.

Has anyone put a switch on the dash anywhere that says CDL of Diff Lock? Not the rotary switch, but a push switch?

 

[Roger Crocker]

That would indicate an issue with the centre diff lock then I'd think. The front and rears only come live when the centre is locked. Unless you do the mod with the plug that we'll get to another day. It could be as simple as the plug to the diff lock not being connected. We've had that before. Some people like to disable the centre locker for manoeuvring caravans and so on. The CDL is electrically fired unlike some vehicles where it's mechanical.

Has anyone put a switch on the dash anywhere that says CDL of Diff Lock? Not the rotary switch, but a push switch?

Aha, Funny you should say that, I wondered why there was a factory fitted switch next to the two electrical ariel switches with CDL on it, I presumed it was so that you could also lock the centre diff in high range, as I was in low box anyway with the light on, didn't think I needed to touch it.
Its really weird having an up & separate down switch for the ariel too.

 

[Roger Crocker]

Will have to take it onto some soft ground now and see what happens

 

[Chris]

Well, you can have this set up in different ways Roger. If you just put the switch in, yes you CAN lock the CDL in high range. And it will still lock automatically in low. But if you pull a plug, you can bypass that and go into low and NOT have the CDL come in. But either way you need the CDL in before the front and rear will fire.

You don't need to be off road to lock the CDL. Switch ign on fully without engine running and press the button. You SHOULD hear 'Bzzzzt' If not then we need to look further at plugs on the box to begin with.

 

[clivehorridge]

Dare I comment, given my track record?

here goes with a ha'penny worth....

Even if the auto Low CDL switch is disconnected but the dash CDL switch is activated, the CDL warning light will show and the rear and front axle lockers should be "live" (they are on mine).

With the unaltered factory set-up, which sounds to be the case for Roger, low has appeared to have auto activated the CDL, 'cos he said the CDL warning light was on, so if the rear and front seem to be dead, no lights at all, first check the dash bulbs (bit of a standing joke for me) then I'd suggest to start testing what's live or not at the axle lockers.

Its not uncommon for the axle lockers to have complexly disintegrated inside, and it's not such a big job to fetch them off and check.

Karl Webster is my preferred and recommended first stop for tested s/h replacements, mr T charges a few arms and legs for new ones. Hope it doesn't come to that.

Now back to Chris to undo all the wrong advice I've just given

Good luck Roger, please keep us updated on any progress...

 

[Roger Crocker]

Hi Clive and thankyou for your advice, funny enough I also have a friend in the VW Syncro Club that has lots of knowledge about those vehicles.
Anyhow since my last reply, I have now tried as Chris suggested & nothing, no buzzer no lights other than the CDL engaged light, cant hear any relays clicking in either, so looks like an hour or so with test meter I guess.

 

[clivehorridge]

Hi Clive and thankyou for your advice, funny enough I also have a friend in the VW Syncro Club that has lots of knowledge about those vehicles.
Anyhow since my last reply, I have now tried as Chris suggested & nothing, no buzzer no lights other than the CDL engaged light, cant hear any relays clicking in either, so looks like an hour or so with test meter I guess.

Sadly I'm stepping into the realms of the unknown, but when I thought I had a fault, the advice I received suggested that the ECU controlling the lockers is low down in the panel to the left of the left (passenger in your case) footwell.

It's a sealed black-box unit, but you could at the least check the connections to it and give it the customary "tap" with a BFH to see if that makes any difference. A live to it when the CDL switch (or low) is engaged would be a start then take it from there.

Again Karl Webster "Karl" on here may be able to assist if you think it's the ECU at fault, just drop him a PM (sorry a "conversation" as it now seems to be known) or contact him at ...

http://www.landcruiserparts.co.uk

 

[Firewout]

My rear difflock was both stuck and had electrical trouble. Wiring loom on top of the rear axle was completely burnt and the relay for the rear actuator on the ecu was toasted too. And of course the actuator was beyond repair as well.
new relay was a cheap fix, new actuator was not cheap. Used a multi core cable to replace the wiring loom