Water Pump Electrics

[mountainman]

I have had a good look through the water pump issues but my problems seems to be electrical and I'm stuck. I have checked the fuse and I have checked the tap microswitch with a multi meter and both seem OK. I have then checked for power at the pump and seem to have .5v whether the tap is on or off, definitely not 12 v. I have checked the power at the fuse and get 12v as expected. So if the fuse is OK, the tap switch is OK, then something is happening in between. Is there a relay involved? I assume there is as the micro switch probably isn't up to the current required for the pump? Also the wiring colours leaving the tap are different to those arriving at the pump.
There seem to be a number of little coloured boxes next to the water pump fuse under the passenger seat. Relays?
Rather disturbingly I found a semi attached piece of yellow wire which seems to have come adrift. Only the main dealer has been in here so god knows what that's about. Pic attached.

But yes, Help!! Please

 

[JohnCalifornia]

Hi I recently fitted a relay to reduce the current going through the micro switch on the tap as the tap was working intermittently. They are not fitted from the factory even though they should have been…… I cleaned the micro switch contacts a couple of times and it worked for a week or 2 before working intermittently again. The micro switch clicked every time the tap was turned on but still didn’t operate the pump sometimes. I’m assuming the contact was bad so wasn’t giving the pump 12v. Have you tried unplugging the tap from its connection under the sink and shorting out the 2 wires to the pump with a paper clip? If you have the factory shower connection you can turn that on to see if it operates the pump. If the pump works with the paper clip or shower method it’s definitely the tap micro switch. My tap has worked 100% fine ever since the relay was fitted as there is no or very little current going through it now and just operates the relay not the pump itself. There are loads of posts on this subject on this forum.

 

[mountainman]

Many thanks for the tip. I have just tried the paper clip thing. Got a pretty good flash but no movement from the pump. I'll check it again but not getting 12v at the pump. Interestingly, when I open the tap I am getting 4-5 Amps showing on the camping display, but nothing else. I'll try putting 12 volts over the pump just to make sure it's working.

 

[mountainman]

I've been talking b******s. Today I realised that I had been testing the water tank level sensor electrics, not the pump. Finally realised this when I took the lid off the water tank together with the sensor float, not the pump! I have been giving the sensor 12 volts thinking it was the pump. Nevertheless, doesn't seem to have done any harm. So, now I'm reduced to a simple problem of a pump failure. Pump now removed and new one ordered. Straightforward from here hopefully.
Many thanks for help though. Hope I haven't confused anyone else.