Glenn Polner

Hi Guys,

I have a 2001 ML 320 April plated.

I brought new washer front and rear pumps and they are not working, i plugged the washer pump in and held it while it was activated and nothing.

I check the steering column stalk blue wire when pulling to activate washer and can see on volt metre this is working.

Is there anything else this could be?

i really appreciate your help

Maj. Dundee

Glen, the front and rear washers work off of two different circuits, so I doubt very seriously it is a power issue.

But both circuits work off of the same ground (W9). Remove the left front headlight an check the ground wires.

Glenn Polner

Thanks so much Maj.

will give it a go tomorrow :-) you should be getting paid for all the info you give out!

Glenn Polner

Hi Maj.

i tested the earth and it works fine, i tested at the connection for pumps and there is none when stalk is pulled, rear one you can hear relay and looks like a small amount of power constant through it?

Maj. Dundee

OK we will have to start from the beginning.

1. The blue wire that you checked, was it in the #20 position?

2. Were you getting a full 12v?


Now we will only work with the front wipers, but for the time being conduct a test on both relays, K17 front and K27 rear. Remove each relay & with the key in the #2 pos, and with a fashioned jumper wire w/ spade terminals attached, test slots 30, 85 & 86 for 12v.

Everything depends on your results of the tests. If you use a bare wire for the tests, you might not make contact with the one contact point in each slot.

Glenn Polner

Hi Maj.

Thanks for the reply,

Front relay, only got 12 volts from jump #86, #85 had .02
Rear relay, 12 volts @ #30, 12 volts @ #86


will retest steering stalk as well




Kind Regards

Maj. Dundee

No just test each slot for voltage. But if the wiper motor does no work, then jump 30 and 87.

Glenn Polner

Hi Maj.

and when i pull steering stalk i am getting 10Volts

Kind Regards

Maj. Dundee

Front relay: stick one end of th wire into respective slot and test the other end.

#30............?
#85...........?
#86..........?

Glen, so we make this simple for both of us, answer questions individually.

Also, you didn't answer the first question. Was the blue wire in position #20?

Glenn Polner

Hi Maj.

Key in to position 2

Front Relay

#30... 0.00 Volts
#85....0.05 Volts
#86...12.19 Volts

Tested the blue wire in position #20...... 10 Volts



Kind Regards

Maj. Dundee

Go to the wiper switch on the column. Pos. #19 grey wire test for 12V. If not, turn wiper on and test wire.

Glenn Polner

Hi Maj,


Key in position 2

Wiper Switch Column #19 Grey wire - Wiper on - 11.82 Volts

Kind Regards

Maj. Dundee

OK, the grey wire supplies voltage to slot #30 at the fuse block. Are you absolutely sure that slot 30 has no voltage?

What time is it in Aust?

Maj. Dundee

Wait a minute.

Was there voltage at the grey wire without turning the switch on?

Glenn Polner

Hey Maj.


When testing grey wire there was no power until i turned wipers on -

Just retested front relay pos #30 no power wipers off
#30 0.02 with wipers on



Kind Regards

It is 5:51pm :-)

Maj. Dundee

Hang on.

Glenn Polner

Ok thanks heaps

Maj. Dundee

While I'm looking at the diagrams, do the following:

1. Replace both relays.

2. Key on.

3. Again test grey wire in pos. #19, with switch off.

4. With switch on.

Glenn Polner

Hi Maj,

1. Replaced both relays.

2. Key on.

3. grey wire in pos. #19, with switch off. zero Volts

4. grey wire in pos. #19 With switch on. 11.00 Volts was varying with wiper motion



Kind Regards

Maj. Dundee

At the switch on the column:

1. Key on test #15 wire Orange for 12v with switch off

2. With switch on.

3. While pulling wash, test #20 wire Blue for 12V.

Glenn Polner

Hi Maj.

At the switch on the column:

1. Key on test #15 wire Orange for 12v with switch off - 0 VOLTS

2. Key on test #15 wire Orange for 12v with switch on - 12 Volts vary with wiper

3. While pulling wash, test #20 wire Blue for 12V. - 10.90 Volts

Kind Regards

Maj. Dundee

OK, now we have to move to the fuse box. Remove both plastic covers. Then remove 3 additional screws and pull fuse/relay module out of box and lay it on its back on a folded towel. Turn key on.

1. Locate connector C/B wire #4 Blue have someone hit the washer switch and you test for 12 v at the blue wire. Results?

2. Then locate connector ML/A wire #2 Blue, have someone hit washer etc. Results?

Note, all connectors run as follows: top row 1,3,5,7 etc. bottom row 2,4,6,8 etc.

Maj. Dundee

I forgot to ask a question.

When you hit the washer switch, do the wipers come on but just the washer doesn't work, or nothing works at all?

Glenn Polner

Hi Maj.


Just started raining heavily and i am working out doors so have had to stop for now, are you thinking AAM? probably why my remote central locking is not working as well?

Will test tomorrow and post results, i can not thank you enough for all your help

Kind Regards

Maj. Dundee

No problem with the rain, I understand.

Tell me what happened. Did these things all go out at the same time. I should have asked you this, but moreover you should have told me.

Also, please answer the question in post #23.