Urgent Help Needed! Window Washer Pump Issues

[si macc]

Got my MOT tomorrow and as its my first MOT ever I totally forgot about the window washers. Yesterday I located the washer reservoir and pump and took them out. I measured the voltage when triggering the washer jets and it was showing 7.3V (or something around that). I assumed this meant the pump was knackered so went to GSF today and got another.

I wired it up this evening and no luck. I tested the pump on the leisure battery and then the main battery and it worked (as did the old one). I found that there was no voltage/no 'clicking' of the relay/wipers moving when the motor is connected which I found a bit strange, disconnect it and I could read voltage again/wipers moving/'clicking' of relay. I have also tested for continuity on the cores but all is fine.

The only thing I have noticed which is a bit suspect is the voltage at the pump end, it was reading roughly half a volt less than the batteries.

Does anyone have any idea on what I can do next to find the fault?

[dj biz r]

not sure but you checked earth wire and fuses?

[si macc]

Hi Dj Biz, thanks for the reply.

I have visually inspected the fuse (will do it properly with my multimeter) is there anything else I can do to check it? How do I go about properly checking the earth wire? (pretty new to car wiring but have basic electric knowledge).

[FergusT25]

Hi. Its just a thought but have you checked the connections on the wiper arm, it just that in the past i have had to clean and bend the connectors to get the pump to work. As i said its just a thought, hope you get it sorted

[dj biz r]

everything has a live feed and earth the earth may just be a brown wire going into loom that is earthed somewhere on body just sometimes a case of fiddle clean tighten sorry cant be more help havnt had this problem yet,,

[si macc]

Thanks both of you for the reply, really appreciate it.

Biz - I have seen the brown earth wire but couldn't locate its end point. Will have another fish around. I suppose I could make my own earth wire and test it that way?

Fergus - Will go and have a look now, thank good for light later in the evening!

[VWCamperfan]

Chances are your earth lead you are looking for runs to the earth crown just behind and to the left of the fuse box. Does sound like an earthing problem and your culprit could well be there!

[Hacksawbob]

Quite possibly the earth is one of the ones on the two 'crowns' that are located behind the fuse box they have a tendancy to get coroded. To get through the mot could you wire a separate feed to the pump?

[si macc]

Thanks all for the continued support!

I have just been outside and did manage to locate end of the brown earth (the crowns you mentioned), though not the exact one... I thought of running my own earth to the pump rather than finding out which one it was. I did this by just wiring up a cable and holding it to the body, this would work right? It unfortunately didn't work.

[VWCamperfan]

Yeah, should have worked providing you had it touching bare metal not a painted or undersealed area (or rusty!).
Could be looking at a switch problem or a loose connection behind switch.

[VWCamperfan]

Just a quick question. Your first post states the voltage was 7.3 volts. You later say the voltage was half a volt lower than battery voltage.
What was the voltage at the pump connections with pump disconnected?

[si macc]

Just a quick question. Your first post states the voltage was 7.3 volts. You later say the voltage was half a volt lower than battery voltage.
What was the voltage at the pump connections with pump disconnected?

Sorry I should have written these down. I did test these again and I remember the voltage was (on average) 7.2V at the pump end (battery was about half a volt higher).

I tested it on a painted bit, better go get the torch...!

[VWCamperfan]

Your batteries flat then! If you measured 7.3 volts and the battery was half a volt higher that would make the battery 7.8 volts... Not the usual 12 volts at least that you need.
I would be checking your battery charge first but have a check of voltages again just to be sure.

[si macc]

I did wonder that but the motor worked on the battery when hard wired to it (though obviously with 1/2 a volt more). I would have thought it would have been unlikely the motor would have stopped working with half a volt less, but as they say 'assumptions are the mother of all f**ck ups!'.

Just tried wiring a new earth to the crown and it still didn't work : (

I noticed the wiper does a weird thing when the pump is connected. Not only does the wiper not work when the I trigger the washer (does when the pump isn't connected) but moving the stalk down (single wipe) the wiper gets about 1/3 of the way, the relay then makes a weird squeeking sound (best description I can think of!) and then carries on! It doesn't do this when the pump is disconnected. Strange.

Looks like I'm gonna have to cancel the MOT and have a look over the next few nights.

[VWCamperfan]

I'm sure its an earth problem. The 'squealing' relay you mention is usually caused by a bad earth. Check and clean all earth connections on the earth crown and make sure none are loose. Not too good now as it's getting dark!