New rear diff lock actuator

[LC80tim]

Hello can anyone point me in the direction of finding this fault, not long had the motor and rear diff locker didn't work, after investigating the rear actuator was totally corroded so bit the bullet and purchased a new one, after fitting said new actuator ( was in locked position and engaged diff lock manually to fit ) on turning ignition on the actuator went to ' unlocked ' position but then wouldn't work after, also the front locker now won't engage ( was working ok before? ) Thinking might be a wiring fault somewhere but a little baffled, so can anyone point me in the right direction.
I didn't spend much time trying to sort as had the BEB to do today ( and boy was it a good job I did ) will post up some pics in another thread later on this one.
Thanks in advance Tim

 

[karl webster]

It's probably the 4wd control relay Tim in the ns footwell.

 

[LC80tim]

It's probably the 4wd control relay Tim in the ns footwell.

Cheers will have a look tomorrow while I'm rebuilding the front hubs lol

 

[Firewout]

Maybe this helps :
I had a burnt relay in the control box and the wiring loom on the rear axle was burnt too. Probably a sticking actuator which kept on pulling current.
Replaced the relay and acruator and repaired the loom.
Everything works fine now.

 

[LC80tim]

View attachment 109498 Maybe this helps :
I had a burnt relay in the control box and the wiring loom on the rear axle was burnt too. Probably a sticking actuator which kept on pulling current.
Replaced the relay and acruator and repaired the loom.
Everything works fine now.

Thanks, more stuff to check, was weird that front stopped working after new rear actuator

 

[Jon Wildsmith]

do you know the centre diff needs to be locked before it will try and lock the front or rear diffs?

 

[Chris]

Quite. And if the rear had been set up in locked position, powering it all up would unlock it, once, and then reset. Which I have to say sounds exactly like the situation you described.

 

[LC80tim]

Yes I realise that centre diff lock has to be on, the new actuator came in locked position, how should I have installed it ? have I done something wrong ? only had experience with air lockers before

 

[LC80tim]

This is what the old actuator looked like

 

[Chris]

Oh boy that's a bad one.

Speaking for both Jon and I, sorry if it was a bit obvious but we've all been asked questions before where all the complicated answers have revealed nothing, then someone says "Is there any fuel in the tank?" Know what I mean? So it was worth asking.

When I fit an actuator that's either new or things have all been to bits etc, I plug it in and let it hang from the loom and cycle the lockers just so I know for sure that it's either locked or unlocked. Then I fit it. The front one is easy, but the rear one can be tricky sometimes. I have found it best to fit it loosely and cycle it a few times before gradually nipping up the mounting bolts. They can jam or bind with only the slightest bias on one bolt hole.

I have done dozens of these, genuinely dozens and even I get the motor and actual state of locker crossed sometimes. As I said for me the starting point is always plug in and cycle it off the axle. If that works great, if it doesn't then it points to a circuit fault somewhere. But whilst it's bolted in place, it's always hard to know if it's electrical or mechanical.

 

[LC80tim]

Oh boy that's a bad one.

Speaking for both Jon and I, sorry if it was a bit obvious but we've all been asked questions before where all the complicated answers have revealed nothing, then someone says "Is there any fuel in the tank?" Know what I mean? So it was worth asking.

When I fit an actuator that's either new or things have all been to bits etc, I plug it in and let it hang from the loom and cycle the lockers just so I know for sure that it's either locked or unlocked. Then I fit it. The front one is easy, but the rear one can be tricky sometimes. I have found it best to fit it loosely and cycle it a few times before gradually nipping up the mounting bolts. They can jam or bind with only the slightest bias on one bolt hole.

I have done dozens of these, genuinely dozens and even I get the motor and actual state of locker crossed sometimes. As I said for me the starting point is always plug in and cycle it off the axle. If that works great, if it doesn't then it points to a circuit fault somewhere. But whilst it's bolted in place, it's always hard to know if it's electrical or mechanical.

thanks will do that first and go from there, yep it was bad just crumbled away, and had to clean all the stuck bits off the axle/diff casing

 

[Roger]

Good call on getting a new motor, in the past I've faffed around re-sticking on magnets to stripping down and rebuilding old ones - which can be a right pain in the butt getting the "clocking" right but they have all had a limited life.

The old knackered ones eventually broke me and I fitted air actuators to both front and rear in the end. Whilst they work very well (and engage slightly quicker) they were a reasonably in-depth project to do, the front one was an absolute pig due to clearance on the anti roll bar mount. The front diff was in and out about 4 times making things fit / clear. The air solenoids sound cool though! - managed to keep it all on standard wiring and switches.

In hindsight, even though the parts for air only totaled up to about £160, I would probably advise to go for new motors rather than the air actuators - purely down to ease / time / convenience. Im not daft with the spanners but they still took a week or so (after work etc) to complete.

 

[LC80tim]

Update, now all working, well I went to do cv's and when I put it on 4 poster ramp decided to see if I could hear motors activating ( quiet workshop ) seems that the wiring to lockers has been altered ( pin 7 mod I think ) if I put it in low the centre diff lock light comes on solid but not locking, so if I press centre diff lock switch it locks, so then tried rear locker and heard motor engage same with front locker both lights flashing, had it on wheel free on ramps so got out and turned wheels by hand and both locked correctly so a happy chappy and cracked on with replacing the cv's
Thanks for all your help and now ready for a lakes weekend as first trip out for the cruiser

 

[clivehorridge]

Good result Tim, I'll bet that was a satisfying moment when you realized you'd cracked it!

Even though all 3 of my lockers work correctly, the dash warning lights have never worked properly.

CDL gives me a steady light, but the rear stays flashing. If I then engage the front, that only flashes too.

As they work properly, it must be a wiring or sensor glitch, but in 11 years as owner, I've never bothered to investigate it.

 

[LC80tim]

Good result Tim, I'll bet that was a satisfying moment when you realized you'd cracked it!

Even though all 3 of my lockers work correctly, the dash warning lights have never worked properly.

CDL gives me a steady light, but the rear stays flashing. If I then engage the front, that only flashes too.

As they work properly, it must be a wiring or sensor glitch, but in 11 years as owner, I've never bothered to investigate it.

yep was buzzing still finding my way round what's been done to truck, found that when i did the cv;s that whoever had been working on it before didn't have a hub nut socket ( chisel marks on nuts ) I got one as soon as I found out size, bit annoying as the one for the disco is 52mm and the cruiser 54mm so had to get one lol

 

[Roger]

Even though all 3 of my lockers work correctly, the dash warning lights have never worked properly.

CDL gives me a steady light, but the rear stays flashing. If I then engage the front, that only flashes too.

As they work properly, it must be a wiring or sensor glitch, but in 11 years as owner, I've never bothered to investigate it.

99% likely to be the plunger switch - very easy fix Clive and less than £20 with these: http://www.ebay.co.uk/itm/Grey-Hous...738514?hash=item51c94ed812:g:SFAAAOSwtnpXps05

 

[clivehorridge]

99% likely to be the plunger switch - very easy fix Clive and less than £20 with these: http://www.ebay.co.uk/itm/Grey-Hous...738514?hash=item51c94ed812:g:SFAAAOSwtnpXps05

Cheers Roger, might give one of them a go at that price, see what happens.

 

[Sarmajornz]

The switches that give the locked feedback are a simple plunger switch used in many Toyota manual gearboxes for the reversing light.
They are available as an aftermarket part.

The problem with them is that they get dirty contacts that do not self clean at the very low currents that the diff lock ECU uses to operate.

You can clean them by hooking up a current limited power supply 24 volts 200 - 300ma and cycling the switch a few times.

 

[TLK914]

I prefer to remove them, depress the plunger ball and spray in contact cleaner...in a pinch some brake cleaner will do. DO NOT use engine degreaser, throttle body or carb cleaner, or harsh solvents as they can damage the switch over time if not immediately. Squirt conatct cleaner or brake cleaner in there and then plunger it like a maniac for 10 or 20 seconds. Then connect an ohm meter between the 2 pins. Should be near zero ohms depressed(Near zero means less than 10 ohms, Ive had them work mostly kinda sorta up to 20 or 50 ohms, more than that is a bad switch. All closed contact switches read OL or millions of ohms released and near zero depressed. Ive had switches that were dead open come back after cleaning, but often they dont. Many switches that cause no lamp have 50,000 or 100,000 or even 500,000 ohms pressed, and OL (zero contact) released. Those ones are more likely to clean up. Electrical circuits require current to flow to perform a job. In this case turning off the light bulb flashes by applying a hard ground through that switch. current is your system voltage divided by resistance. you started with 12 lousy volts. 1 or 2 ohms still can flow 6 amps (voltage divided by ohms = amps) and that light bulb requires maybe 1/2 or 1/4 of an amp to be affected. 12v divided by 100 ohms or 1000 ohms leaves virtually no current flow to ground...light wont be affected.

Its all about the continuity to ground...nothing more.