He took his diesel fed Webasto HL 32B out to do another immediate task (plug a hole

I managed to download a service manual but it is really all greek to me and my poor brother. And we tried various methods and wiring variations without much success. We got fan spinning in heater but no pump. And round other way etc.
As this equipment is fairly old and expensive we we're keen not to burn out any part. In all there is a thermostat. An on/off switch. A silver box of tricks with three plastic numbered terminal connectors. A pump with diaphram. A cuddly toy . Whoops! Be serious for once

So what we're after is a kindly soul or souls, brimming with sagacity, to take a gander at attached photos and hopefully write a basic, moron friendly list telling us what numbers on the Webasto silver box does what or goes where:
like this for instance;
A1 is live wire to thermostat.
A2 is earth.
--------------------
C3 not required.
C5 is to battery + terminal .............. and so on please.
Terminal blocks and numbers below
99 percent of wiring below

Pump and diaphram...with only one wire? Surely not!
Eternal gratitiudes to any replies that may help my brother. How he's survived so far is beyond imagination.
Not your average southern shandy drinking softy me thinks
