windshield wiper return issue

[shanegtr]

Just wanted to see what everyone thinks of this. My wipers work fine when moving from the parked position up to the top of their movment, but on the way back around half way they stop and wont move again unless you give them a little shove and they continue to the parked position. Any ideas what could be going on here?

 

[chengny]

Just wanted to see what everyone thinks of this. My wipers work fine when moving from the parked position up to the top of their movment, but on the way back around half way they stop and wont move again unless you give them a little shove and they continue to the parked position. Any ideas what could be going on here?

Sounds like the NC switch in the parking circuit is not making contact (and thus failing to provide a path to ground) until the very end of the downward stroke.

When in low speed, the LO speed brush is connected to ground through it's own dedicated lead and dash switch - the motor runs continuously. But, when the dash switch is toggled to OFF, that path is lost.

At that point, the Park circuit takes over and provides a temporary path to ground for the LO speed brush.

There is a cam in the parking section that - when the blades reach the park position - opens the NC switch. So, when there are no grounds available - the wipers stop.

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To confirm a bad park switch just jump across the terminals as shown - and described in the diagnostic text. Leave all other wiring connected as normal - including the leads to the park switch.:

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If the blades still fail to return home - with the jumper installed - the problem is with either the associated wiring or the dash switch itself. Be aware that - with the park switch jumped - they will continue right on running. Just as if the control switch was in low speed.

And also, if you have the intermittent wiper option, there might be a problem with the pulse module. When those modules are failing they can make the wipers seem like they are haunted.

 

[shanegtr]

Many thanks for your information. I shall test it all out. I do have the intermittent wiper option on mine.

 

[shanegtr]

And also, if you have the intermittent wiper option, there might be a problem with the pulse module. When those modules are failing they can make the wipers seem like they are haunted.

Had a little play around with the wipers this evening. Interestingly I have no intermittent wiper function - they just run on the low speed when any of the intermittent speeds are selected. Might look at replacing that pulse module. Jumping the park circuit I get similar results to before where the wiper will get about half way on its return to the park position and stop - Seems like the motor is struggling to drive the wipers because if I lift one wiper blade off the screen then it dosent have an issue. Seems to run in both low and hi speeds - although theres not much difference in the actual speed. Possible that something is binding in the linkages or the motor is just a little weak. Seems to stop around the same spot everytime so I'm going to look into how free the linkage setup is for movement with the motor disconnected

 

[shanegtr]

Need a bit of a thread dig on my own thread here. So I haven't really looked into this issue much since 2018, but for us here in Australia winter is on its way so I'd like to sort this issue before then. Whats changed since I last posted is a new pulse module and new wiper motor. Both of those replaced back in 2018, and neither have made any real difference. Today I've pulled the motor and cowl to check how free the linkages are and if they are binding anywhere in the movement and it all seems nice and free with no issues.
So at the moment I'm kinda stumped as to whats going on. From the above reply's I dont belive its an issue with the park circuit as it happens when the switch is in any run mode - intermittent, low or high. I cant remember what happened when I jumpered terminals 3 and 4 as it was several years ago when I last played with this, but I'll do the test again. Fairly sure it still struggled to return.
Could the dash switch itself have a high resistance and no allowing enough current to drive the wiper motor? Or maybe a poor earth after it?

 

[shanegtr]

Ok, so Ive been playing around with this issue over the last 3 or 4 days and I believe Ive found my issue. Even with a direct cable to the motor from the battery the wipers still struggle, even on a wet windscreen. Mechanically the linkages are very free and require very little effort to move. Without the wiper arms attached I only need a loose grip with 2 fingers to move the linkage the full range of motion. However once the arms and blades are attached it all changes, requiring quite a bit of force to overcome the friction between the blade rubbers and the windscreen. I'm going to try new wiper blades first and if that makes little difference then I'll have to look into maybe a lighter spring on the arm to reduce the pressure on the windscreen