Jurgens palma tap - RVs

There should be a tag on unit somewhere telling you both of those things.

red line goest to water heater, blue line to water pump, but they may be tapped into other lines

These trailers are made in sold in South Africa, it appears.
As such, please type the 1996 Jurgens Penta Caravan into the search engine of your computer, and you will find them for sale. ( I did)
Call someone who is selling one and ask them the tire size.
We are in the USA, and see no way to help you here.
God bless your efforts.]

Please restate your answer in the form of a question.

check you fuse on top of your pumps one of tour valves could be stuck. tap lightly with hammer

check the piping to the shower for damage, kinks , blockage
check that the washer in the tap is not expanded and blocking off the flow of water

guessing here

one would be to the fresh drinking tank
leaves two to choose from
does the RV have two types of taps ?
how many water tanks on this model ?

have see one layout with chemical toilet and normal house taps at its sink
or kitchen sink with multiple taps

If it's 12volt DC, splice in to closest light in ceiling.

Isn't there a tap on your side that you might need to open ? (on the Outback's side of the hose?)

Are all the relevant taps turned on?
Is there water coming out of the city water ?
Are all the taps "along the way" open?
If hose stiffens up when you open the "city" side tap, then clearly there is water pressure and the tap on your side must be closed
Best of luck