How to fit a rear mounted screenwash bottle & make your own catch tank

I’ve found this which looks good but it has separate pumps. Would I be right in thinking that a push on the washer stalk sends a positive to the pump and a pull sends a separate positive? If so the positives could run one each to the separate pumps? Or does the MK2 pump work differently?

 

It reverses the polarity to the mk2 pump, to make it pump to the rear.

 

I should go and look on the car but it’s cold, are there three wires or two?

 

2 wires I think.
Mk4 golf has a nice tank and twin outlet pump, was going to fit it in drivers side to clear my air filter, but managed, got one here if want pics or it @PhilRyder

 

Whatsapp incoming

 

2 wires, call them A and B. A is + and B is - for front wash, flick the stalk the opposite way and A becomes -, B becomes +. There's one way valves built in too, to stop both front and rear spraying.

 

WhatsApp outgoing.

 

My galaxy had that, and a cracked valve housing on the pump, fine on front screen, but if washed your rear (cue @costel1969 ) it would push the split open and empty the tank.

Golf mk4/bora tank, tucks in nicely, thanks to @rubjonny for alerting me to the usefulness of them .