Thread: ISSUE: reverse lights/Diff lock warning light

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

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.

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...

Cheers - Gav

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...

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

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?

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.