Windscreen wiper problem

I have a defender 90, TD5, 04. The windscreen wipers have started to do there own thing. The intermittent function will start off with the normal 1 wipe then pause but then goes off on its own with 3 or 4,5 or 6 wipes between pauses. Then it will go into normal continuous operation. The problem then is that they will not turn off. I try selecting other position but no go, they keep going. I don’t think it is the stalk switch because if I flick on then off they will stop. The problem occurs after they have been on for a few minutes.
Any ideas out there. Is there a wiring diagram available? I would like to see what other components are in this circuit.?
With winter coming I would like to sort this out.

Thanks in advance

Rog

Assuming the TD5 wipers are the same as earlier defenders, there's a permanent live feed (for the auto return) and a little spring set/relay built into the motor unit. These go out of adjustment/break commonly. Easiest fix is to replace the unit, or if you're handy, it may be possible to repair the spring set/relay.

Thanks I will have a look

In my case the key thing in fixing my wipers that worked when they felt like it was replacing the wiper control relay, which in TD5s of that vintage is behind the instruments. My old one fell apart in my hands as I tried to remove it and the new one has been much more reliable. They call it a 'wiper relay', but there's a lot more than a relay inside, including a printed circuit board so plenty to go wrong. Anyway, much cheaper than a whole new wiper motor. There may be a fault also with the wiper stalk switch on the steering column - I've noticed the contacts in those can be a bit iffy.