For a more thorough run down on how to repair these problems we suggest either –
I recently had the joy (ha ha) of helping a friend diagnose a problem with his Mitsubishi Pajero. I suppose you couldn’t even call this vehicle modern as it was a 1993 model. I hate to think what problems a 2007 model will cause down the track! The problem we had was with the ‘Super Select’ system, which when working allows you to select four wheel drive on the ‘run’. A great system no doubt, but not something you would want to stop working halfway through a drive to the ‘back of Bourke’ (a long way from civilisation for those outside Oz!)
The system has five earthing switches on the transfer case and gearbox, a small control module, two vacuum switches in the engine bay and a vacuum operated gizmo (the technical term!) to engage the front hubs. That to me spells trouble in itself, a complicated system on a vehicle that is designed to take you places you normally wouldn’t go with a conventional car.
The first issue was the green lights on the dash flashing, indicating that the hubs where trying to lock in even though the transfer lever was in two wheel drive. We tracked that down to the ‘gizmo’ on the front differential housing had vacuum to only one side of it’s diaphragm. To keep the hubs in the unlocked position it needs a vacuum supply to both sides. O.K. so once we swapped the vacuum hoses around and provided vacuum to the other side the actuator and the hubs retreated into unlocked position and the lights on the dash went out. Yee-hah. So now we had to work out why the vacuum had disappeared on one side only. We checked vacuum supply to both solenoids, checked vacuum hoses for splits or damage and checked power and earth supply to the solenoids. All good, except for the earth supply for the solenoids wasn’t great, but we reasoned if that was the cause then both solenoids would be playing up as they are wired in series. Checking the solenoid’s resistance revealed a huge difference in the two. Problem one, need to replace solenoids.
I was still concerned by the quality of the earth provided to the solenoids. Probably not causing too much drama but just not right. We found that by using a test light connected to the positive terminal of the battery and the probe stuck into the negative side of the solenoid connection, that when we earthed the wire at the gearbox switches the earth improved drastically. Why were the switches on the gearbox and transfer case not giving a good earth? Only way to find out was to pull them out. Luckily we were doing this in a garage and not on the side of the road, bit of a mission! There was two switches that our earth wire was joined to, one on the gearbox and the other on the transfer. When we unsrewed these we found that someone had obviously tried to fix this problem previously. Where the wire goes into the switch there was lucky to be two strands of the wire left!
Because the wire comes out of the side of the switch, not the top, as you screw them out if you are not careful the wire twists around itself and breaks. Luckily we were able to solder another piece of wire to what was left coming out of the switch. Another problem we found was that the switches themselves had a reasonable amount of oil inside them, not good for providing an earth. So we cleaned them out as best we could, carefully re-installed them and now we had the test light glowing like a champion. Problem two, near broken wires and switches full of oil.
We ordered new solenoids from Mitsubishi, they only come as a pair even though we only need one! Just shy of $200.00 which I think is reasonable. We have just fitted them today and it all works like a charm. Problem solved. Looking at four wheel drive forums and web pages, it seems this problem is very common with Pajeros. For my dollars I’d much rather have the slight inconvenience of getting out of the vehicle and manually locking the hubs in, rather than relying on electronics to do it for me. You don’t want to be second-guessing when it comes to driving in difficult terrain. A brilliant idea no doubt about that, but poor execution.