Centre diff lock light playing up

[Aeroelastic]

Hi all, I am new to this forum and fairly new to Landcruiser too. Bought a 97 Colorado 3.0td manual last winter and love it.

Has been visiting this forum few times but just registered yesterday. It’s a great forum with lots of information and people are helpful here.

I have an issue with my Centre diff lock bulb in the dash. My timing belt light came up few weeks ago and I reset it this weekend, took the cluster off and managed to reset the timing belt light. While I was in there I replaced the old bulbs with new LEDS too. Looks fantastic. But now when I engage the centre diff lock, the orange indicator light in the dash sometime doesn’t light up immediately, but if I wiggled the steering slightly then the indicator light will come on and works normally.

Anyone can figure out why? Can’t remember it behave like this before I reset the timing belt light. Thanks in advance.

Forgot to mention, my centre diff lock is the lever engage type, not the press button one...

 

[diggerdave]

If it was like that before, it's possible that the switch screwed into the side of the t/b has deteriorated (or its wiring is fubared). It's the same plunger-type switch as the reverse light switch, though I can't recall if it's exactly the same switch.

When my reverse light switch failed, it went through a period of delayed action and sometimes working sometimes not before failing completely.

In a sense that would be my best guess. Otherwise I'd suggest a failing bulb in the cluster, but if you've changed all of them (and the others are working) that is less likely....

 

[Bert]

..... I replaced the old bulbs with new LEDS too. Looks fantastic. But now when I engage the centre diff lock, the orange indicator light in the dash sometime doesn’t light up immediately, but if I wiggled the steering slightly then the indicator light will come on and works normally....

Hello Aeroelastic.

First thing, where on earth did you find LED's for the cluster bulbs? I'd love to replace some of mine. If you have a link, please send it.

Secondly, I have a '97 Prado import. Sometimes when I try to engage the centre diff, I have to jiggle the lever, or, I have to first go forward a little, or reverse a little, before the light pops up. Always keep the wheels straight when doing this.
Other times, I engage the lock and the light doesn't come on, but after a biut of travelling a short distance it sometimes does. It is a little frustrating, but (I'm not an mechanic) I think that sometiems it needs to be "in the right place" before it properly engages. So, it may not actaully be the light, just the fiddly way the diff does, or does not always engage first time.

 

[diggerdave]

Edited for wrongness (see my post below)

I agree with that - it just depends how 'bad' it is whether it's a problem to be fixed or not.

However I don't think its to do with the centre diff lock engaging/not engaging. I think that the centre diff lock always engages (and disengages) when the lever is moved unless there is a serious fault within the T/B that would be evident in other ways.

The indicator light on the dashboard is triggered by the plunger switch that is located on the side of the T/B. The plunger is activated by the position of a selector shaft inside the top part of the T/B, which is in turn moved directly by the T/B lever in the cab.

So the light is triggered by the position of the T/B lever. It is NOT triggered by the actual locking of the centre diff as such; it doesn't 'know' whether the CDL is engaged, it only 'knows' whether the selector shaft is in the right position to engage the CDL.

Any problem with the dashboard light will be related to the plunger switch mechanism, NOT to the actual operation of the centre diff.
Delayed light operation (minor)=plunger switch sticky/worn/not quite engaging properly with the selector shaft/they all do that
No light or major delays= plunger switch faulty (or wiring)

That's my understanding anyway.

 

[diggerdave]

On the attached diagram the relevant switch is 'centre diff lock indicator switch'. It works by the plunger engaging with a cutout/dimple on what this diagram calls 'front drive fork shaft' [the cutout can't be seen on the diagram because the shaft is facing the wrong way, but it's similar to the cutouts on the 'high and low fork shaft' which operate the 'transfer neutral position switch' (I think only on autos) and the ''transfer low position switch'].

 

[Shayne]

I'ts's because it now works better than it did , imagine a sprung pin pressed against a solid turning wheel looking for a hole to drop into , when things line up the pin springs into place and your locked and lit up .

Its a warning light so you don't forget to unlock more than anything else .

 

[diggerdave]

I thought I'd better check that what I wrote, and I got it wrong - sorry.

The plunger switch is actually operated by the CDL fork NOT by the selector shaft. When you shift the lever, it shifts the selector lever, and then a spring-loaded fork attached to the lever activates the CDL when the necessary teeth line up or deactivates it when enough load is off the splines. As Shayne says, 'when things line up'.

Much better explanation from someone who knows these T/Bs well on this thread, 6th post: https://www.landcruiserclub.net/com...ff-lock-not-releasing-light-going-out.130598/

So the indicator light IS directly related to the CDL mechanism contrary to what I said before and it does 'know' if the CDL is engaged or not.

However I still think the plunger switch should be the first check, assuming the the CDL is working as it should.

 

[Aeroelastic]

OMG! Can’t believe the replies I got from you ... thanks a million guys, very informative. So as soon as the lever is shifted, the light does not necessary comes on immediately? Not even the flashing light? Until the plunger aligned.

One big Q, if the light never come on but I know the CDL is physically engaged, will I be able to lock the rear diff? i.e. does engaging the rear diff relies on the CDL light being on?

Some photos of the LEDs below, maybe not everyone cup of tea but I like it. It modernised my 21 year old rig. I didn’t swap all the bulbs, only the main ones for the speedos and fuel and temp gauge. 4 no.s T10 bulb and 1 no. T5 bulb. The rest in the centre console are all T5. Details see next reply. Both from Amazon.

 

[Aeroelastic]

Two types of bulbs:

T10;

https://www.amazon.co.uk/Grandview-...d+60+lumen&dpPl=1&dpID=41JlFdkBzaL&ref=plSrch

T5

https://www.amazon.co.uk/Aerzetix-L...d+red+bulb&dpPl=1&dpID=51kPr8D+nKL&ref=plSrch

The T10 ones are brilliant, works first time.

4 of the T10 are required in the cluster. With 1 T5 at the bottom of the speedo near the 0mph position. These are bulbs with dark green holders, you will understand what I mean when you remove the cluster and look at the back of the circuit board. Basically their holders are different colour from those warning light bulbs.

The T5 needs a wiggle sometime to get them light up.

Needed 2 T5 behind the clock, 2 behind the knobs for fan control and 1 for the ashtray and 1 near the cigarette lighter charging point.

Remember, LEDs are polarised, if first time didn’t work pull it out and reverse it and try. Make sure all bulbs work before putting things back...

 

[diggerdave]

So as soon as the lever is shifted, the light does not necessary comes on immediately? Not even the flashing light? Until the plunger aligned.

Yes. When the lever is moved there will be a period of time before the spring-loaded shift fork actually shifts (until everything is aligned), at which point the CDL engages or disengages. The plunger switch detects the movement of the shift fork so the light won't react until the shift fork moves (engaging or disengaging the CDL).

One big Q, if the light never come on but I know the CDL is physically engaged, will I be able to lock the rear diff? i.e. does engaging the rear diff relies on the CDL light being on?

You won't be able to engage the rear difflock unless the T/B is in low range. There's an ECU involved, which 'knows' whether you're in low range because it gets a signal from the other plunger switch on the other side of the T/B (which incidentally DOES work off the selector shaft).

Whether the plunger switch for the CDL also has to be operational (i.e. whether the ECU also takes a reading from the CDL switch as well as the low range switch)... not sure. I vaguely remember reading somewhere that the only switch that matter to the ECU is the low range switch, but I'm not trusting my memory right now!

 

[Jake the Peg]

Have a look on Joom.com for LED bulbs, keep searching through the listings, you will get 10 delivered on the slow boat for £1/2 and in a whole bunch of colours

cheers