4WD lights flashing and switches not working

My 2011 Jimny with dash switches to select 4WD has developed a problem, here is what happened.

I parked part on the kerb to go to the post office this morning, when I got back in and set off the 4WD green light was on solid on the dash, the 2WD/4WD drive switches didn't do anything and it felt as though it was in 2WD, there were no clunks.

Unfortunately there is no where to park round there so drove about 3 miles to work, taking it very gently.  During the drive the 4WD light and 4L light came on and started flashing about once or twice per second, the switches were still not working.  It has the feel of something electrical, perhaps a sensor/switch or something?

After getting to work, I switch everything off, waited a couple of seconds and started the car, the 4WD light has gone off, but the 2WD/4WD switches don't do anything.  If it is stuck in 2WD (which I think it is) at least I can drive around, but need to get it working correctly, especially with bad weather coming.

I know there is a good guide on the wiki, so lots to work through, but any suggestions where to start would be useful?

Robin
 

Sorry should have said, I didn't engage 4WD, it just came on all by itself. It wasn't on when I parked up and didn't notice if it was on when I started up or if it came on when driving up the road, but it was definately on after 50 yards.

Does the 4WD light come on if the vacuum fails? I suspect it doesn't which is why I think it might be electrical.

Further testing.

I left my Jimny for 30 minutes, went out started it up and it went through 2WD, 4WD and 4L correctly, I tried it several times.

Then with the engine running the 4WD light came on all by itself and I am back in the same position as before. I actually think the hubs clicked when it did it, so it might be in 4WD.

I am guessing that if I leave it for a few minutes it will drop out of 4WD.

I never had a similar problem but I would suspect an electrical problem. To solve this, I would first have a look at the switch and also clean it and then check the cables from the switch to the controller.

First off look up at the transfer box and decide what is happening with the wires feeding the box it could be obvious that something has fallen off or snapped. After that you need to electrically test for continuity voltage resistance etc in the loom and also the transfer box switch After that it's taking things apart time.

I checked it again, the 4WD was trying to engage (flashing prior to starting the engine, so not enough vacuum), but the 2WD switch turned it off.

I think it is definately electrical, almost as though something is chaffing and telling the unit to go in to 4WD. Or perhaps one of the relays is sticking?