Sudden Differential Lock Red Warning light

Hi, can anyone help. When reversing a heavy trailor this afternoon the Diff Lock warning light came on, (I never knew I had a diff lock fitted); when I selected neutral or forward gears the light went out but was still there when I selected reverse again. Then I discovered that it came on when ever I put my foot on the footbrake. This problem continued after I dropped off the trailor

The warning light isn't on when the ignition is on unless I put my foot on the brake or select reverse; the handbook say that if the light is illuminated when the starter switch is turned on, it means the diff is locked. I certainly havn't locked the diff and it hasn't had any garage work in that area for others to have engaged it, but then again the light isn't on all the time. Can anyone offer any ideas on where the problem lies?

sounds like a dirty connection on your tow bar electrics,
give them a good soak in wd40 an see if that helps.
Nick

Thanks nickh75, i'll give it a try.

I'd agree. My trailer warning light that should flash when towing and indicating sometimes didn't. Checked the caravan, replaced some duff-looking wiring, changed the connector etc all to no avail. Finally got round to the Landy socket and all looked well and clean until I opened it up ... large ball of rust, it's a wonder anything was working ... changed the socket, all well again!

Hi all, thanks for your help. Discovered in the end that it could be an indication that a bulb might have blown somewhere on the vehicle; on checking everything over discovered that the reversing light fuse had blown - problem solved.

Nice one. Thanks for posting back what actually fixed it, might help others.

That leaves the question, why had the fuse blown? Did it have something to do with plugging in the trailer?

Good question, I discovered that the cable to the trailor I used had been damaged by the hand brake system, that,s been fixed as well. So Davec you were in the right ball-park. Many thanks.

it is common for the diff lock warning light to come on when the fues goes because mine does it to gave me some head scratching when it first did it the problem is it still blows every now and again (1-2 times a month) but cannot find the fault

I got the same symptoms today as described:

During towing a trailer I started getting the diff lock light when I pressed the brake pedal, and now the brake and reversing lights don't work.

I have checked the fuses and can't find any blown, I checked every one with a light symbol because I didn't know which was the right one.

Can anyone suggest a cure?

Check fuse F25 interior fusebox

Well done sierrafery.
I replaced the tow power socket which was grungy as hell, and found F25 had blown by going through each fuse one at a time. Problem fixed! Thanks for the hint.