ISSUE: reverse lights/Diff lock warning light

[JMAN]

Hi all, my reverse lights are not illuminating when they should and the diff lock lamp on the dash is not illuminating.
Where do I start looking and what is the fix for this?
the globes are all good....

[Homestar]

I have the same issues with my 85RRC - they are low on my list, so haven't investigated either of these yet. Apparently they both worked before my father in law took it to a Rangie 'Specialist' and had some wiring 'fixed'. The stuff he wanted fixed then worked :) , but it created other problems :mad: . I will be looking at mine soon, and I will post the results, if you haven't got it sorted by then...

Cheers - Gav

[JMAN]

no worries mate. I'm led to believe these two particular things are wired in the same circuit....
I've had the reverse light switch out (from under the car attached to the top of the gear box). The diff lock engages but no light...
If I get it fixed I'll let you know.

[Ace]

Im no electrical expert but find the wiring related to the two and start at the bulb and work backwards till you find a section with power to it, then find where its loosing power and fix it.

Are the fuses all good?

[JMAN]

I had the gear box replaced sometime ago and everything is plugged in as should be. I was hoping for a loom to be unplugged somewhere!
The engine check light illuminates, as does the parkbrake, highbeam, low fuel, indicators, hazards etc.
The reverse light switch terminals are riveted down but spinning/moving 360deg, the plunger is clean and moves in and out nicely, I've tried screwing it in/out but nothing is activating the lights.

I rang a reputable company about this today (who shall go unnamed), for some advice and to that person I spoke to: if you're reading this, get another job pal. You clearly hate talking. I never assumed you were an auto elec but bloody hell, you do work for a land-roverparts distributor!

[JMAN]

fitted a new reverse light switch just now but the lights are not illuminating at all. However, the diff-lock warning light is on and stays on in all positions of the changer (won't turn off). Time to call an auto elec? The CDL light stays on also when the gear changer (manual) is not in reverse. It's just on no matter what and still no reverse lights.
There's 2 wires going into the far side of gear box (driver side) I cant tell what these wires are for and cant see where they go to exactly. Does any one know what they are for?
Also where are all the fuses/fusible links for the reverse lights?

[JMAN]

Lights operating with new switch. The issue was that when the gear box was changed over, the three wiring looms, one for the gearbox temperature, one for reverse lights and one for the difflock were all in the wrong places. The only issue I have now is trying to locate the difflock switch from under the car as its totally obscured somewhere on the driver side. It's gonna have to stay unplugged for the time being until the day I can find it with my eyes closed and hand feeling in the dark. Thanks for your help everyone.

[Homestar]

Cool, well done. You work faster than me - I still haven't got around to looking at mine - but I may do this weekend, as the weather looks good.

Cheers - Gav

[JMAN]

Another thing, I managed to solve water ingress problems. I had water coming into the footwells and on close inspection I found the rubber at the bottom of the windscreen had tucked itself into the plastic air cover. I used a small screw driver to lever it out. Also used silicone to seal the metal clips around the gutter. I left the car outside during the heavy downpour we had last week and not a drop inside.

[JMAN]

the CDL switch is not working either. So gonna get another. Took some time on google images finding a picture to locate where it sits on the transfer case. Took it out, cleaned it up, screwed it back in up and down switched wires etc etc but no go. Not a blown fuse otherwise I wouldn't have reverse lights or indicators. Also got a new stepper motor coming as I've cleaned it and the mounting plate on the plenum too many times as the idle speed is very slow to drop from 1500 down to a nice idle. So I'm crossing my fingers hoping that these new parts will sort out these issues.

[Homestar]

Did you check the CDL switch with a multi meter while you had it out?

[Bigbjorn]

The reverse lights on an Isuzu are wired through an oil pressure sender. They only work when the engine is running.

[JMAN]

The wiring loom for the CDL works because I had it plugged into the reverse switch and when ever I put the car in reverse the CDL light in the dash would come on. plugged it back into the CDL switch (after I took it out and cleaned the switch and terminals) no CDL light appeared. It took a fair amount of mucking about getting under the car time after time. I took a mutli meter to the switch a few times out of the car and also when it was connected up to the Transfer case. Dont really know what I'm doing and blew a fuse once, a 10amp.
On first and close inspection, the terminals were bent inward and the black plastic box looking thing in between the terminals appeared burnt/slightly melted and greyed. I've played with the positioning of the switch like i did with the reverse switch and I reckon it too is no good. Strange though how both are buggered at the same time. The new switch is coming from England and as soon as I get it in the car I'll post the results.

[Homestar]

If you blew a fuse on the multi meter, you may have connected a voltage accross the leads of the meter while you had it on the ohms scale.

I am still watching with interest, as I have yet to try and fix mine...:p

Cheers - Gav

[JMAN]

My new stepper arrived today. In between ordering and it arriving I checked every hose etc for vacuum leaks. Couldn't find one leak. Today I fitted the new stepper I paid $50 for and blow me down, what a difference! No more high revs 1500-2000 at the lights and the revs drop immediatley when you put the clutch in. It feels like a new car. I reckon I'll save on fuel somewhat.
The CDL switch has not arrived yet but am hoping it will tomorrow. bacicat2000, make sure your looms are going to the right switches. Mine weren't connected to their mate. The CDL loom when connected to the reverse light switch illuminates when I put the thing in reverse but not when connected to the CDL switch, thats why I'm confident the switch is dead.
The fuse I blew was one of the ones under the steering wheel, the one for the Reverse light, indicators...

[JMAN]

still waiting on the diff lock switch... bought on ebay and being sent from UK.

[JMAN]

I put the new switch in and now...wait for it.... the CDL light is ON when in high range (normal highway driving) and turns OFF when changed to diff-lock...

What is going on?

[Homestar]

Sounds like the switch is normally closed when it should be a normally open type. Not sure if there are more than 1 type of switch for this - maybe someone else can shed some light on it. You could use a relay and some wiring to invert this, but it is a bit of stuffing around...

Just had another thought - has the switch got 2 or 3 terminals? If it has got 3 terminals, then it has both NO and NC contacts in it, and you may just need to move a wire.

[JMAN]

It's only got the two contacts. Push the "button" in and the light comes on. I hand tested it and this is how it works.
The transfer case is the original one... but maybe something inside it has jumped off an landed on the high range??? Perplexed big time...