Hi everyone, new member here with yet again another washer pump mystery.

So I've tried all the usual fixes ie -fuse, new pump etc etc... 

I put a multimeter to the connector at the pump and there's no power going to the new pump, so I check the fuse diagram under the passage glovebox and it reads - fuse number 136 which I thought should be a 15 amp fuse. To add my confusion I see a 25 amp fuse (clear fuse) in the 136 spot and it's slightly corroded. 

Please can anyone tell me if I'm missing something here? 

My BCM is the same layout as the diagram below. 

Much thanks in advance,

Nullig 🤯

 

The operation of the screenwash pump is controlled by the BCM.

If you have tested or replaced the wiper/washer operating stalk and it is fine then you need to check the BCM for signs of water ingress/corrosion of the connectors and of the circuit board.

Thanks for the info Unofix. I forgot to mention in my first post, that I did indeed change the stalk and that worked the same -wipers work but no sound from the pump. I kind of hope its not corrosion on the BCM obviously, but can you shed any light as to why there is a 25amp fuse in the 136 pin which should have a 15amp in there? I know its hard to say but any ideas would be helpful. 

Just a thought, it may have been mice or a rat that chewed up the wiring as I live in the countryside and its like the Serengeti out here at the best of times.

I'll check the wiring again in more detail at the weekend and post back here if I solve it.

Thanks again for your input.

35 minutes ago, Nullig said:

as to why there is a 25amp fuse in the 136 pin which should have a 15amp in there? I know its hard to say but any ideas would be helpful. 

During the production life of a vehicle it is common for Fuse ratings to be changed by Ford. I note that on some cars that same fuse also supplies the heavy duty headlight washer pump, so it may be they just changed it for that reason. Then of course there is the possibility that previous owners may have had problems with the screen wash pump blowing the fuse and so they thought it would be an idea just to put a bigger fuse in.

Remember when you test the wires at the actual pump motor that you need to test them one at a time, with respect to the battery negative terminal. When you operate the washer switch for the front one of the wires will be positive, and when operated for the rear screen the other will be positive.

I suspect that you have a break in one of the wires, so testing each with respect to the battery negative will show which one is faulty. It could be that the fault is actually inside of the BCM

Thanks once again Unofix for your input and taking the time to reply, very much appreciated!

 

16 minutes ago, unofix said:

when you test the wires at the actual pump motor that you need to test them one at a time, with respect to the battery negative terminal. When you operate the washer switch for the front one of the wires will be positive, and when operated for the rear screen the other will be positive.

Please excuse my ignorance but can I do this with a multimeter?

I'll do as you suggested with testing the wires at the weekend and post back.

Thanks again,

Nullig

Yes you can test for voltage with a multimeter. 
 

With some extra pieces of cable you can possibly test the circuits for continuity, you’d need to disconnect the relevant plug from the BCM though. Don’t think you could check from the fuse pins as it needs the BCM to activate the internal relay

Thanks Troy, good idea and definitely worth a shot to narrow It down.

 

Yes as confirmed @troy45 has said you can test the voltage using the multimeter.

Connect the negative lead of the multimeter to the battery negative terminal. Disconnect the plug from screen wash pump. Then connect the positive lead of the meter to one of the wires in the plug and operate the washer pump switch, first for the front and then for the back screen. Repeat the process with the other wire.

Will do and thanks for all your help and advice, very much appreciated!

Nullig

21 hours ago, unofix said:

connect the positive lead of the meter to one of the wires in the plug and operate the washer pump switch, first for the front and then for the back screen. Repeat the process with the other wire.

One last thing and again, excuse my ignorance... should I put the multimeter on the continuity setting?

Thanks again.

That’s correct, multimeter on continuity setting - helps if it’s got a setting that beeps for zero resistance. Test this by touching the 2 connectors/probes together 👍

6 minutes ago, Nullig said:

should I put the multimeter on the continuity setting?

No. You are testing for voltage, not the resistance.

You need to set the meter to read Volts DC

 

4 minutes ago, troy45 said:

That’s correct, multimeter on continuity setting -

The OP is meant to be testing for voltage at the screen wash pump when he presses the button on the stalk. The meter needs to be set for Volts DC

Thanks very much again fellas🤞