1980 westy joker water tank gauge black wire help

should the  black wire that connects to the lowest point on the fresh water tank be live cause i thought it was an earth wire? mine reads 3 volts. reason i ask is because filled the tank up went camping turned tap on and no water lowest red light is lit up on the control panel. tested pump and tap switch both work fine. disconected black wire on water tank gauge thats reading 3 volts, put a wire in its place and ground to earth top green light on control panel lights up but still no power going to pump or tap. disconected contol panel put white live wire from panel switch to yellow pump wire, turn tap on i have water.

Edited by moogster - 06 Jun 09 at 14:39

Thanks for the reply the wiring chart i have in the early joker book is different to the one on the link on this forum.  I know the tap should only work when the switch is switched on on the control panel.  Just wondered if anybody could check to see if there is a volatage reading on the black wire which is the lowest terminal on the gauage on the side of the fresh water tank, that according to my wiring diagram should be the earth . If i remove this black wire and put a wire on the terminal and touch it to the body work the green light on the water level meter on the control panel lights up, draining the water the lights go down yellow onto red. But the tap is still not working unless I bypass the system completely.

Thanks Andrew is there a part/ serial number on the regulator on yours? as the number on mine is not clear enough to read. The electric wizard at my work is going to try fix it, if it works i will let you know and send the part over to you to fix yours if you want.

No, Günzl haven't got it.  Will look later today and see if there's a number on the part concerned.