Sorry I'm not going to be much help, but when you say "If I engage the wipers before I turn the ignition, they will briefly move and then stop when the engine has started, so there's a point on ignition that says for them to work", this is not a fault & is normal operation.
First position on the ignition switch turns the ignition ON. When you then move to the START position certain auxiliary circuits are disconnected to reduce un-necessay drain on the battery while the engine is being turned over to start.

You don't say what year the van is, does it have automatic rain sensitive wiper function ?
Is the vehicle battery in good condition ?
Could the vibration caused when the van is running and/or moving be causing a loose connection ?
Does the intermittent wiper function work OK ?
Are you sure there is only the one relay in the BCM that is involved with the wiper circuit ?
Have you checked all the earth points in the circuit, especially the motor, are in good condition. Not just tight, but a good electrical connection ?

 

Sorry, just noticed you have said what year it is !! 2005

 

It could be the J519 under the dash. It's well known for causing wiper problems. As for why they only stop at idle, the only thing I can think of is that the same box controls the electrical load sensing so perhaps that is something to do with it.
http://www.brick-yard.co.uk/forum/o...ltage-supply-unit-j519_topic92128.html?SID=62924-89bc7d85c84dd82aebfe7119444444

 

Thanks for the replies,

It doesn't have a rain sensor, battery is in good condition and works well.
Not sure about the vibration to be honest as nothing changes it apart from stoping and starting.

I swapped out the relay in the control unit which is for the wipers, the common one most people have tried.

Earths are all good

I'm thinking is it a complete control unit replacement?

@t5tdi
By the j519 do you mean the complete unit (Bcm) ? Or do you mean a relay?

Thanks for your help

 

@t5tdi
By the j519 do you mean the complete unit (Bcm) ? Or do you mean a relay?

I know the thread has moved on now but for others who tread this way- On the 2003-2009 old model vans there are two boxes that control most things that are not directly engine related. One is the J519 which is described in my link above or here and the other is the Central Convenience Control Module (J393) which is under driver's seat.

If you want to connect to these boxes individually with VCDS the J519 can be found as Address 09 and the J393 is as address 46.

On the new model (2010 on) the two boxes are combined and commonly get referred to as a BCM (Body Control Module).

 

The electronic box of tricks under the dash, just above the throttle pedal designation J519 is officially called the Onboard Power Supply Control Unit & is often confused/misdescribed with/as the BCM, Body Control Module. I've got a sneaky feeling that the BCM is found in VW cars & although it may be the same or similar in operation for some reason it's called a different name in the vans.
I could also, of course, be wrong !!
All I can tell you for certain is that a 2005 T5 only has the Onboard Supply Control Unit.

 

Hi CAT3,

Sorry that's the box i mean, the control unit. That's the only thing i think it could be.

 

The only thing that I can think of trying, before spending a load of your hard earned cash is to see if you can find out which plug in the control unit has the connections from/to the wiper stalk & wiper motor. It may be that there is more than one plug involved here, possibly two.
It might be possible to make some temporary connections to bypass the control unit. Because the control unit houses the wiper relay, bypassing this could confirm where the fault lies. If it's possible to make these connection & the wipers work then that confirms that all the external wiring, switches & wiper motor are OK.
The control unit may well have other internal connections to the wiper circuit on the PCB, but I'm sure you must be able to get the wipers working with this unit out of the circuit.

One word of caution though. The relay is used for a reason, to reduce the need for heavy gauge wires & switch contacts up to the stalk switch itself. If you can get the wiper to work by bypassing the control unit you MUST NOT leave them running for any length of time as you could quite easily damage the small gauge wires & switch contacts of the stalk switch itself !

 

Great, that's definitely worth a shot. Its annoying as it is a MOT failure at the moment, but my garage has passed it two years running, as they know they work when i'm driving, its taken a while to find out what this fault is. Thanks for you help

 

This might be worth try, not saying it will work for certain, but worth a try. Also, don't be sending me a bill for any damage caused, be it on your head !!!!

The Onboard Control Unit, (J519) disconnect plugs "D", (connector T5, which should be BLACK) & "I", (connector T18a, which should be BROWN).

Lift both the front wipers off the windscreen to reduce any friction if they move ! This will reduce the current flow should the wiper motor operate.

In the BROWN connector "I" look for a WHITE/GREEN wire, which should be located in pin 11 of that plug.

In the BLACK connector "D" look for a GREEN/YELLOW wire, which should be located in pin 2 of that plug. Also, the GREEN wire, which should be located in pin 3 of that plug.

You should see that these wires in these two plugs are different gauges, which gives an indication that the current flowing in the wires will be very different !!
I'm guessing you'll have to turn the ignition ON to switch power ON so do that first.

Switch the wiper stalk switch to the POSITION 1 NORMAL WIPER, NOT THE FIRST INTERMITTENT POSITION.

MAKE THE FOLLOWING CONNECTION THIS NEXT STEP VERY BRIEFLY to keep the current flow to a minimum.

Now using a suitable length of suitable gauge cable with suitable contacts on each end, connect this link wire between the WHITE/GREEN wire of the BROWN plug & the GREEN/YELLOW wire of the BLACK plug. Hopefully the wipers should now operate, if they do not try connecting the WHITE/GREEN to the GREEN. I think the two wires in the BLACK connection are for the two speeds of the wiper motor, but I'm not sure which is which.

If all goes well you will be connecting a power supply from fuse SB10, through the wiper stalk switch & to the wiper motor, jumping out the control unit, it's PCB & relay.
Hope it goes well I:

 

In my previous post I said the WHITE/GREEN wire was in pin 11 of the BROWN plug, I should have said pin 18. Sorry !!

Before you do the above test, (if you decide to try it !!) try this if you haven't already done so.

Disconnect the BROWN plug at the control unit. Turn the ignition ON, but DO NOT start the engine. With a multi-meter check for voltage at pins 18, 14 & 11 as you make the various selections below on the wiper stalk.

You should get 12v at pin 18 when you press the stalk down for a single wipe & when you select position 1 for slow speed.
You should get 12v at pin 14 when you select position 2 for high speed.
Select INTERMITTENT wipe position & on pin 11 you should get varying voltages as you also select the various intermittent speeds.

If you get no readings at any positions try starting the engine & repeat the test.

Results;
With no voltage readings with the engine NOT running the fault is NOT with the Control Unit, (J519).

 

Hi, I've just had something similar happen on my 2006 T5, the wipers would stop and would only work if I gave them a shove. They would work if it was raining - as the water was lubricating them, but stop mid cycle when the rain stopped, therefore more friction. They would also stop when pulling up at junctions etc. Whilst idling.

After checking all the electrical contacts, which were ok,it turned out the joints on the wiper mechanism had seized causing the motor to burn out! Replaced motor and the wiper mechanism and all works fine now!

 

Mdgiles has already changed the motor. Don't know if it was with a new one or a second had one.

 

CAT3

Thank you so much for the advice, when i get home tonight i will try that to eliminate the Control unit.

Fella1971

Yep i have changed the motor out completely.

Thanks all for you help and advice

 

Ah sorry, didn't see that!
Problem with mine came from the joints where the wiper arms attach to the mechanism under the windscreen seizing, replacing the whole assembly solved it.

 

Did yours work again as soon as you started moving? They will work as long as i am moving, whether or not its raining.

 

Mine were so weak, they wouldn't work without me physically pushing the arms to get them going. Occasionally they would work if I turned them on, but not very often. If I was driving and it started raining I would have to pull over and give them a push, they would work but not as strong as they should have done, then if I pulled up at a junction, or it stopped raining they would just die.
I'm no expert, but could that be down to more power running through the electrical system when it's running at higher revs giving it a bit more oomph to overcome a stiff mechanism?
Maybe a squirt of penetrating fluid in the mechanism to help it run more freely!

 

Ah okay, i've had a new motor on it and mechanism. No change, they work great when moving

 

Ah, only other thing I found when investigating mine was a brown earth wire for the wiper motor under the plastic scuttle panel to the right of the wiper mechanism in a rebate that had filled up with , I gave this a good clean in the process.

 

Another thought has crossed my mind.

When you start your engine & start to move you say the wipers start working. At a standstill they don't ?

Have you tried starting the engine & just increasing the revs, (to a constant level above tick-over, maybe 2000rpm) without moving ?
Does this have any affect on whether the wipers work or not ?

 

Looking like its the Control unit! Damn, off to ebay i go and get one reprogrammed.

Thanks for everyones help