Rear washer electrics

Can someone please give a novice amateur motor electrician a few pointers on how to diagnose a fault with a Discovery 2, TD5 rear washer?
The rear washer has not worked since I bought the vehicle last year. I accessed the pumps in front of the near side wheel arch and tested them by swapping the front and rear pump electrical connections around (so that the front washers were connected to the rear washer switch and vice-versa). When I did this, the rear washer worked but the front washer didn't, hence the fault is not the rear washer pump but somewhere in the electrics of the rear washer.
Looking at the manuals, the rear washer seems to be on the same fuse as the wing mirror adjusters, but my wing mirror adjusters work. Does this therefore mean that it must be the rear washer switch or a wiring/connection fault?

Id first check fuse 30, in the passenger footwell, as that supplies the voltage to the pump. since you've already proved the pump works.... but I see that you have checked the mirror motors work.

Next, Id check the operation of the switch with a multimeter..

If you have the maintenance manual, its page 1263.

https://www.ebay.co.uk/itm/Land-rov...777079?hash=item2cf5a4c437:g:jioAAOSw0rdde4sP

For less than a fiver, you could replace it and rule it out....

Page 166 on this might help you...... http://www.discovery2.co.uk/pdf_files/D2_electrical_library.pdf

Hi, When I had a problem with the rear wash it turned out to be the none return valve in the fluid pipe just inside the door panel.
Griff

ANR said:

Does this therefore mean that it must be the rear washer switch or a wiring/connection fault?

Click to expand...

Very likely cos the rear washer has a very simple circuit: fuse - switch - motor, so measure if you have 12V against earth on the switch's pin 1(green/light green wire)

Great. Thanks very much. I'll investigate further.
Andrew

With the engine ticking over I'm getting 32V on line 1, and 0V on line 4, against earth, see pic:

I should have mentioned this earlier but the switch activates the wiper arm but does not activate the washer pump. And as previously mentioned, I know that the washer pump is working having swapped over the connections at the reservoir (i.e. the front washer switch then activates the rear washer).
Can someone please advise on what to check next or what to do please?
Thanks.

Double check your multimeter cos it's impossible to get 32V there unless the battery clamps are loose and you measure direct alternator output which even then is too much. Anyway, make a bridge across pins 1 - 4 and if the motor starts the problem is the switch

Thanks very much Sierrafery.
I'm going to buy myself a new multimeter and re-access the pump and reservoir, then test everything again.
My multimeter is a cheap version, and I'm still getting 32V at green wire terminal 1. The battery negative terminal 'lug' is tight but it can be wiggled off by hand. I wonder whether the earth is not good, and whether this could create a 32v readout? The probes are quite short and the best unpainted surface I could reach was a bolt on the door frame or the door frame clasp.
Making a bridge between 1 and 4 pins activated the wiper but not the washer. This is my problem: wiper works, washer doesn't.
So, I'm going to try again at the weekend, with a better multimeter.
Best wishes,
Andrew

ANR said:

Making a bridge between 1 and 4 pins activated the wiper but not the washer.

Click to expand...

Then the problem is not the switch that's certain, you'll have to troubleshoot beyond that based on the diagram from header C0293 where the signal from the switch which reached the BCU from there splits to the pump too

Stick your meter across the battery with the engine ignition off... just to see if its working properly. You should get just a happy 12v DC.