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Can anyone help with my Passat wiper parking problem? They only park when in 'intermittent' mode, or being pulled in 'screenwash' mode. When switching off from slow or high speed they just stop immediately no matter where they are on the windscreen. I would be grateful for any ideas......
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A simple self-parking wiper motor uses a separate direct(fused) 12 volt supply to drive the self-parking mechanism. This is built into the wiper motor and operates independantly of the dashboard switches and wiper relay.
You can see the need for this separate supply if you park the car with the wipers sticking up out of position. As soon as you turn the ignition on, the wipers should immediately self-park.
Unfortunately, this simple design doesn't explain the way your wipers manage to self-park in intermittent and screenwash modes. I can only assume that the Passat's electrics are more sophisticated in these modes. Though have you tried turning off the wipers while they are half-way through an intermittent wipe - I bet they don't self-park then!
So the first step is to test if there is a 12v supply on any of the wires connected to the wiper motor (ignition on, wiper switch off). If there is, I suggest you have an internal fault in the wiper motor.
If not, you will need to trace back the wiring. It's unlikely to be the fuse, because the (simple) design will probably share the same fuse as the rest of the wiper circuitry, and you would have a complete wiper failure if the fuse had blown.
Ian
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I thought the wipers used a relay? if so this is likely to be faulty
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Many wiper systems have a permanent supply to the motor;the system is controlled by earthing the other side of the motor.
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I don't know what year your Passat is, but I've been looking at a diagram for a '97 model, and also a mid '90's Golf, to get an idea of how Volkswagen wire their wipers and they seem to use a universal (for VW) system.
I think the fault could be with your switch, although I don't really understand why the wash/wipe parks in the right place.
I'll start with a basic check you can perform, and if you want (and are able!) to do a more detailed check, just let me know.
With the ign on, operate the wipers then switch them off when they have done a half-wipe. Assuming the wipers are now stuck half way over the screen, remove the wash/wipe relay and check for 12 volts at the relay socket relating to relay pin marked 4 (or 53s) (ign still on). There should be 12 volts.
(If by chance there isn't, move the wiper switch to the int wipe position and check again. If there is now 12 volts in only this position, then I would the be 99.9% sure that the switch is at fault.)
Assuming the switch proves to be faulty, with the ign turned off operate the switch quickly through its full travel up and down a few times to see if perhaps a little bit of dirt has got trapped in there, and which may just release with a bit of vigorous movement! Actually, on second thought, try this first.
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Thanks for your interesting suggestions - [it's a 94 GL 2.0] - I think IanT must be right. I remember dismantling a motor/drive assembly when it failed a few yrs ago, I think there were two separate partial circular contact strips on the flat cog driven by the worm gear, one for the 'normal use' parking and one for the 'intermittent use' parking, presumably.
I suspect a new assembly is needed.
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Quote:-"I think there were two separate partial circular contact strips on the flat cog driven by the worm gear,"
If I'm correct, one of these strips would be nearly a full circle (pos. supply for parking), and the other would be the size of the gap of that circle (neg. supply for quick stopping of motor).
I've found the wiring diagram for your model-year on the web, and it proves to be the same as I had been looking at as mentioned in my previous post. For self-parking, the circuit relies on a contact in the motor, the wiper switch position, and the wash/wipe relay switch contact. If one of these items is faulty, the wipers will not self-park.
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In spite of John F's vote of confidence, I have to concede that Andy T is right. I've now had a look at the Haynes wiring diagram for a 94 Golf (near enough).
The wiper motor is as I described it - all the mechanical and electrical bits for the self-wiping mechanism are built into the motor and the self-wiping mechanism has its own power supply direct from the fuse. BUT (and it's a big BUT) the 12v self-parking supply enters the motor on pin 1/53A and then immediately leaves again on pin 3/53E to follow a tortuous route through the wiper switch and the relay/timer to re-enter the wiper motor on pin 4/53.
This is wired up so that the (self-parking) 12v is only delivered along this route when the switch is in either the intermittent or off position, AND the intermittent timer (in the relay) is not asking for another wipe.
So a fault in the motor, the switch or the timer/relay could affect self-parking. But you say your system does self-park when used in the intermittent mode, so on balance, I now think the switch is the most likely candidate - the switch not making good contact when returned to its off position and therefore not forwarding the self-parking 12v back to the motor.
Ian
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