R

Repoman

Member

• Nov 21, 2016

• #1

hi

I would appreciate some diagnostic help with my 93 Defender 90. The problem is that neither the front nor rear screen wash is working. Here is what I have observed / tried so far

The washer bottle is full (!)
All fuses are good
All connections seem to be good
The pump isn't making any sound
Both front and rear wipers are working OK

As there is no sound this seems to be an electrical problem rather than a blocked pipe.

Some basics. Is there one pump that operates front and rear? Or...At the bottom of the tank each supply pipe seems to connect into a separate cylindrical shaped thing that also has the electrical feed to it? Are these the pumps? seems weird that both would go at the same time.

Thanks!

 

flat

Well-Known Member

• Nov 21, 2016

• #2

Probably pump failure.

Easy way to check would be to use a multimeter and check voltage at the plug for the pump while someone presses the button. If voltage is present its the pump that failed so just replace. If none then probably a broken cable or the switch is bad at the steering wheel end

 

Flossie

Well-Known Member

• Nov 21, 2016

• #3

Sounds like you have twin pumps if you have 2 tubes from the tank. As Flat says you need to check for 12v at the plug with a multimeter or bulb set up.
However... Both pumps may have a common earth and if that's broke/loose/ whatever, then both pumps will stop working simultaneously.

 

J

Jam1

Well-Known Member

• Nov 21, 2016

• #4

Mine has twin pumps and both run off the same positive

 

Flossie

Well-Known Member

• Nov 21, 2016

• #5

Jam1 said:

Mine has twin pumps and both run off the same positive

Click to expand...

They must be switched by the earth then.
If that is the case then it's back to using a multimeter on the live feed at the pump to a good earth, if it reads 12v then put the earth lead off the meter to the earth at the pump and press the switches in the cab, if no reading it's wiring or switches, if you get 12v then the pumps are dead.
I'm no electrical guru but ( to the OP) get a multimeter(they are cheap) learn some basic stuff on how to use it and you can fix stuff like this all day long.
Great for checking for broke wires , bad connections, charging issues etc etc.

 

doriz

Well-Known Member

• Nov 21, 2016

• #6

Might be worth putting a current across the pumps themselves to ensure they are functional. Thinks the wires are black/green iirc. Electrical snags are great fun to diagnose and very satisfying to fix.

 

R

Repoman

Member

• Nov 21, 2016

• #7

Great. Thanks for these responses. I do have a multi meter but also a fear of using it... The fact that both pumps are not working does point to the failure of a common piece of wiring, either earth or supply so I will have a look at the weekend.

I have recently swapped the dash illumination for LED's but I cant imagine there is any relevant wiring there that I have disturbed?

 

J

Jam1

Well-Known Member

• Nov 21, 2016

• #8

Flossie said:

They must be switched by the earth then.
If that is the case then it's back to using a multimeter on the live feed at the pump to a good earth, if it reads 12v then put the earth lead off the meter to the earth at the pump and press the switches in the cab, if no reading it's wiring or switches, if you get 12v then the pumps are dead.
I'm no electrical guru but ( to the OP) get a multimeter(they are cheap) learn some basic stuff on how to use it and you can fix stuff like this all day long.
Great for checking for broke wires , bad connections, charging issues etc etc.

Click to expand...

No I should have been clearer, I think a previous owner just wired both into the same switch because they wanted the space the rear washer switch sits in for toggle switches or broke the switch and found out how much they cost

 

doriz

Well-Known Member

• Nov 21, 2016

• #9

My rear washer switch broke and I just replaced it with a standard one but kept it all separate.