Thread: Should I panic? Diff lock light not coming on immediately

Originally Posted by NT5224

As it says in the title, my centre diff light doesn’t always come on when we lock it. Anybody else have this issue and any suggestions?

Alan

It comes on when the CDL actually engages, not when you move the lever. So, it should come on after you move the car a bit with the lever moved to the 4WD position. If it's not doing that then you have issues.

ZIG ZAG.
Regards PhilipA

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Originally Posted by NT5224

As it says in the title, my centre diff light doesn’t always come on when we lock it. Anybody else have this issue and any suggestions?

Alan

Sort of have these issues now and then. Sometimes wonder if Land Rover should have bothered with the light switch on the gear box and light bulb on the dash.

Your title implies the light always turns on, but may take some time on occasions. Has it never come on when the lever position indicates it should?

Provided your linkages are connected, and even if a bit worn, the locking ring has no choice but to go where you tell it, via the lever.

You get a satisfying feeling through the lever when the lock ring engages correctly. And that feeling through the lever is not just feedback of movement of the lock ring - a detent ball bearing is also locking in your selection. Sometimes the lock ring splines don't line up first time, and you know that because the lever just doesn't seem to have moved enough and the lever is still free playing because the detent ball bearing has not been able to engage. Roll the vehicle a bit to get better alignment.

The light switch has a probe that rides/tracks a slope during the movement of the locking ring. When pushed high on the slope the probe completes the circuit, and the dash bulb lights up. When the probe drops off the slope the spring loaded probe returnes to the off position.

If your linkages and internal movement components are slightly worn it may be possible the slope has moved just fractionally short of its full range, thus not lifting the light switch probe quite high enough to complete the circuit. However, as you drive forward, for a few seconds wondering where the light is, the whole kit finally seats itself fully and the light comes on. This could be exacerbated by wear on the tip of the brass probe (although writing from memory it may have a ball bearing tip instead) and possibly wear on the slope itself. A cam and selector fork are also involved, the selector fork more likely to sustain a bit of wear.

I've opened 5 boxes, one with over 600,000kms; they're very robust provided you lock 'em when required and also service the brass shims in the centre diff - although a torque bias diff replacement is really the best choice.

As already said, range of movement of the lever is a good indicator, moves proper distance and held by the detent, then highly likely engaged - the light switch can entertain itself

As an aside, in the opposite vein, if you ever have a light on the dash, but it takes a while to turn off after unlocking, then the light switch probe probably needs a clean and lube.