Diff lock switch replacement

[Alex Roux]

On my latest trip the diff lock light on the control panel started flashing for now apparent reason. The diff lock was not engaged prior to this. Then, exceeding 30 km /h the diff lock alarm started to go off!.
So the car was convinced my diff lock is engaged, when this was not the case.
So the immediate solution - disconnect the wire at the back. Otherwise the diff lock alarm would have driven me crazy.

Now that the car is in for a service this is being looked at.
The Nissan service centre's feedback is that the diff lock switch is broken and will cost me about R9,000 to replace!

So questions:
1) Why so expensive?
2) Could this be a good time to replace the diff lock system with ARB air lockers (then at least I have lockers front and back)?
3) What other options do I have?

[Grootseun]

Alex , i dont buy that one , are they trying to tell you that the switch on the dash where you switch it on and off is R9K - hell that cant be , why dont you hook up with someone with a similar Patrol , swop the switch over to confirm and then take it from there , im sorry but i cannot see a simple litte rotary switch goign for that money

[Jules]

Alex do as Grootseun said, I had the same problem on my GQ, fitted Peter C switch when I was in Harties area, problem was initialy the switch " later the solenoid due to not being used enough", Peter C boet made a copper relay and my one jeweler buddy fixed the plastic with asetone ( plastic welding agent ), cost R80 compared to a quote from Nissan for R1200 if I recall correctly.

Maybe they also sommer want to replace the "actuator" , I think that is what it is called????

Daar is n paar manne op die forum watse switches ook lawaai het en het net n goeie skoonmaak gekort.

Shalom
Jules

[ChristoSlang]

Alex, the difflock on the Patrol is mechanical (vacuum-operated), with electrics to activate it and signal the state of the locker...

The switch inside the car operates two solenoids (one at a time) under the bonnet that open and close vacuum line s running to the rear diff. Turn the switch one way and one of the lines are activated, turn it the other way and the other line is activated. The vacuum pulls an activator inside the diff to engage and disengage the locker. It's easy to check them by disconnecting the lines (hoses is probably the more appropriate word?) at the back one at a time. With the switch in one position, one of them should have a vacuum with the engine runing and the other not. Turn the switch and they change places - the other one's now got the vacuum. Low vacuum on only one of them indicates a blocked/leaking vacuum line, or a faulty solenoid. You can isolate the cause by swopping vacuum lines - if the problem changes to the other hose it is solenoid-related. Low vacuum on both hoses is more likely to be a leak/obstruction between the vacuum source (alternator, diesel pump. etc. - depending on the year model) and the solenoids. That's the vacuum mechanics in a nutshell!

The elctrics are just as simple: when you turn the switch on, it also sends an intermittent signal to the light on the dash so it starts flashing. This merely indicates that you want the locker to work and have signallled your intention to the vacuum solenoids. It does not mean that the locker has engaged yet. There's an additional feedback circuit (screwed into the side of the rear diff) that indicates when the locker is properly engaged. When the locker's internals slide into the locked position, it closes this circuit and sends a permanent electrical signal to the diff-lock warning light which now stops blinking and stays lit permanently. There may be overrides involved that check for low-range, vehicle speed, etc. depending on year model. These sender units sometimes misbehave and do not indicate a properly locked diff, but they are generally fixed by disconnecting & unscrewing them, then sanding them with fine paper to make sure that the single moving part operates smoothly.

So... by the sound of things you have an electrical problem with the switch only. I'd recommend that you test it by turning it off and checking for vacuum on one side, then turning it on and checking for vacuum on the other side. It the vacuum works as intended (switches from side to side at the rear locker), you probably have a short in the wiring between the switch and the instrument cluster causing the light to activate when it should not. If the vacuum does not switch from side to side however, it's likely that the locker's switch is to blame. You may then swop the vacuum lines around at the diff as a further test - if the locker light is now lit permanently (regardless of the switch position) & the rear diff is actually locked (you'll want to test this on a soft surface!), my bet is that the locker switch is in fact knackered as they claim...

Driko is right, that price is highway robbery! My Patrol's locker is broken, but I have no intention of getting it repaired as it will cost many times more than the switch. I'm sure we could make a plan with the switch if you are in the Gauteng area. Join our Nissan 4x4 club (it's dirt cheap!), pop around to the dyno day on the 28th of January (that one's free for club memebers) and we can chat again...

[ChristoSlang]

Oops - forgot about other options!

You can look for a switch in scrap-yards, but Patrols are rare. This will be much cheaper if you can find one! Maybe the Navaras, etc. have similar switches?

Or you can go for an aftermarket locker. An ARB will require you to install a R3000 compressor to activate it (without which you'll get no warrantee) and then also cough up another R15000 for the rear locker alone. If you want a front locker too, you'll need a bigger ARB compressor (meaning more expensive!) and more money for the front locker itself.

These are estimated prices, YMMV...

[Herrie]

My Patrol's switch on the rear diff was stuck because of dirt and the light kept flashing even when the difflock engaged.

I just took the switch out the diff, cleaned it properly and it still works fine.

[Alex Roux]

Air lockers are great but probably a bit stiff and budget won't really allow it right now.

Christoslang: I just verified with Mcarthey Nisssan Randburg: It is the actual elecrtic swith in front itself that is faulty.
The new one is R10,800 to source and replace!!!!
The guys at the service centre are apologetic though. They can only provide me with the quoted firgures as provided to them.

I am a Nissan 4x4 member and may attend the 28 Jan meeting. If you are going to be there, please let me know.
Pitty, it would have been great to attend the 21 Jan Sandwani track.

[Peter Connan]

Alex somebody is rolling you a mielie.

I think it is probably the solenoid (the interface between the electronic system and the vacuum system). This is inside the engine compartment, bolted to the firewall.

How to test it for yourself: there are four pipes connected to this solenoid, two on the side (which then enter a little manifold, are consolidated into a single slightly larger pipe and goes to the engine somewhere) and two on the front face. these two pipes go to the diff. with the engine running, unplug each of these two pipes. When you unplug one pipe, you must hear a sucking noise. Then switch on the diff lock switch on the dash, and do it again. This time the sucking noise must come from the other pipe.

I suspect you will find that there is no sucking when the diff lock is switched off, and if this is so, then the diff lock could engage even when the switch is off.

If this solenoid is not working, you can try and dismantle it and clean it, or you can replace it. I bought a new one less than three years ago for less than R3000 from Nissan, so they can't now be charging that much for it, go to another Nissan agent. Alternatively, search this forum for PECS's posts, and use their solenoid. It is much cheaper.

If it is not that, then: if there is no sucking noise no matter what you do to the switch, then it is a blockage in the vacuum line or the dash switch or electrical wires between the two. Take of one of the pipes at the side of the solenoid, there should be vacuum there whenever the engine is running. If that is fine, check that there is power at the solenoid with a multi-meter.

If all the above works, then the switch at the diff becomes the suspect. I am told this is the Nissan 1400's reverse light switch. Get one, and fit it and see if it works or enscrew the switch and test it.

[ChristoSlang]

My Patrol's switch on the rear diff was stuck because of dirt and the light kept flashing even when the difflock engaged. I just took the switch out the diff, cleaned it properly and it still works fine.

Yep, that's the one that signals when the intermittently flashing light should remain on. It plays no part in the actuating of the locker itself, it's merely an indicator that the locker has engaged. The locker is actuated by the vacuum lines. But it can defintely be confusing if it does not work properly!

I'll be at Sandwani and the SAC Dyno Day. We can swop locker switches there to confirm the diagnosis...

[Alex Roux]

Hi Christo

Brilliant, Thanks. See you then.