Hi Everyone, I'm new here so please forgive a topic which may have been done to death.
My background is field service engineering, so I am used to finding obscure problems and repairing them without the benefit of all the spare parts!
The rear screen wiper on our Mk2 Scout became intermittent and then stopped all together a while back, and I think I've round the solution!
In this case though its not obscure at all - it's a very common issue with any system where a printed circuit has solid connections to the outside world, especially where these connections are the mechanical anchors for the board.
The rear screen wiper drive assembly contains a small PCB, with connections to a 4 pin connector (earth, +12, and two control pins). Internally, here are two connections to the motor which are made via soldered pins within the assembly - and that's the problem. In my Skoda Scout, the soldered joints on these connections were "dry" where either due to poor soldering at manufacture or vibration induced fatigue failure of the solder, the joint looses integrity.
It's simple to fix if you're handy with a small soldering iron - and a breeze if you have prior experience as a hobbyist in electronics.
Getting to the assembly inside the rear door is the hardest part - popping the cover off - but I'll leave that for you to look up how to do this on this site and or any number of others!
I removed the whole drive assembly - unplug the cable, take off wiper arm, and remove three 10mm head bolts, but if you're a contortionist you might be able to do the job without assembly removal.
You will see a small rectangular cover (about 35mm X 25mm) on the front (/back?!) face of the assembly near the connector - use a fingernail to get it off, a screwdriver is not required.
You'll see the PCB as in the attached picture (sorry about focus but its good enough!). I have arrow-ed the two offending connections. If you use a decent magnifying glass youll see that the solder around one or both the pins looks like its cracked and crumbly - that's classic "dry joint" appearance!
Ideally, remove the existing solder (with solder wick or a "solder sucker") and then carefully re-solder those two joints. If you can't remove the existing solder, though, just apply a minimum amount of quality resin-cored (electronics) solder and apply enough heat to allow the solder to flow around the pins. Inspect the joins to make sure the surface is nice and shiny with no cracks. Incidentally, the joints on that board look too shiny to be ROHS compliant non-Lead solder, so you might find old school lead-tin solder if you have any, will be easier.
Clip the cover back on, reconnect the cable and give it a test - in my car (2l Diesel Scout) the engine has to be running for the rear wiper to work (that had me tricked for a while! (-: )
Respond with any comments or questions! As a newbie, I welcome constructive input!