Wipers won't park


Wipers Won’t park.

Effects:
Jaguar XJ-S to 1988
Jaguar XJ6 Series III

Article by: Steve, SK Jagtech
Additional Contributors:Christo and Jeff
Published: April 2006
Body open time: 2 hours

Click image for bigger version
NON PARKING WIPERS. Hasn’t happened to you yet - it will.

This is the most common problem with the XJ6 series 3 and XJ-S pre facelift that crops up when dealing with the wipers.

To describe this was always going to be very difficult so please read the information carefully and have a copy in your work area using the Printer friendly version

The problem stems from how it works. The picture above shows the switch exploded on the bench and has a modification to it that is a workable repair, for how much longer is not known, it could be a year (unlikely) or it could go another 10 years (more likely)

The tip off ‘C1’ on the switch arm runs against ‘C1’ in Part ‘C’. The other side ‘A1’ of the switch arm moves across ‘A1’ of part ‘A’, as it does so, part ‘A’ moves up and down inside slot ‘D’ under spring pressure. Part ‘A’ has copper contacts on it which connect to wipers inside slot ‘D’ that are in turn crimped to the wires coming out the back of the switch, this is how the mode is changed - Off Intermittent, Run and Fast.

The fault occurs due to the contact edge, ‘A1’ on ‘A’, wearing down along with A1 on the switch arm consequently A does not move far enough down to make the Park contacts align.

The repair can be seen as item ‘C1’. In the part ‘C’, it’s a piece of plastic; the type found under circuit boards, you should be able to just see it under the arrow.

This thin piece of plastic (0.5 mm) means the tip of the arm now runs across this and is forced further down against part ‘A’ causing the copper contacts to align correct when the switch is returned to Park.

‘B1’ is a bearing and dimple arrangement to make the switch act positively between positions.

The repair can be carried out as follows.
Tools and Parts:

Drill and drill bits
Thin piece of plastic
Scissors
4 x 2Ba 1 inch bolts (#4 in the USA)
4 x 2ba Nuts
Dremel style tool
G – Clamp
Volt/continuity meter (VOM)

 Click images for larger views

A note on the type of nuts: These need to be thin, otherwise they will interfere with the mounting plate if they are too thick. There is a recess in the mounting plate and a raised area on the switch where it contacts the plate. So there is about 1 to 1.5 mm clearance. At the other end of the switch the mounting plates shape means it won’t interfere with the other bolts

  1. The first task is to drill out the rivets and carefully separate the two halves of the switch body

  1. Set the main part of the switch to one side and firmly clamp the metal part of the body to your bench. Using your Dremel type grinding tool remove the rivet posts right down their full length. Even with the Dremel this is harder than it sounds

  1. At the bottom drill small 2 mm holes for the bolts to pass though as close as you can to the space vacated by the original rivet posts

  1. Using the thin plastic sheet obtained to create a spacer. Cut it to shape to fit the area as per the drawing and use some glue to fix it into place

  1. Turn your attention to part ‘A’ in the main picture: it would be a good idea to clean the copper contacts and corresponding contacts in the slot ‘D’ another idea that would be good is to turn the copper contacts over to the unworn side which is straightforward

  1. It would also be prudent to use electrical grease on the moving parts

  1. Now the tricky bit, reassemble the switch A extra pair of hands helps here, you need to make sure that the switch slider Part ‘A’ in figure 1, is slightly depressed into the body down slot ‘D’ and that the Ball Bearing is located under the switch arm. Carefully lower the body ‘C’ back into position and Clamp the two halves back together with the G Clamp. Now test that in park; pins 5 & 6, 1 & 7 are connected. Move the switch to run and then back to park and again check that you have continuity on 5 & 6, 1 & 7 still. Once again move the switch to RUN and carefully watch your meter as you slowly return it back to the Park position the Continuity should be visible just as the switch snaps back. If any of these tests fail you need a thicker plastic spacer to affect the repair.

Pins 5 & 6 B/G & U/G
Pins 1 & 7 G & K/G

 

  1. If all worked out OK you can proceed to the fixing up stage. Bolts through the two holes ‘2’ can be inserted from the metal side through the original rivet holes in the main body and be fitted with nuts. The other two that go through holes ’1’ might need to enter via the plastic end and you may need to grind a little bit off the side of the head in order to get it to fit but this depends on the bolts your using. Again obviously fit the nuts and tighten. The protruding thread needs to be trimmed back flat with the nut head on these to avoid the interference mentioned earlier.

  1. Another contributor, Jeff suggested an alternative means of securing the two halves back together: “run steel wire through the original rivet holes on the plastic piece and through the new holes in the metal. twist the wire tightly to squeeze the two pieces together”. the wire should be insulated inside the switch body to avoid short circuits.

  1. Refit the switch back on the car and enjoy the fact that your wipers now park were they are meant to

As it may also be helpful to know the connectoions on the bulkhead connector they are included here for reference

Lucas Wiper motor connections Technical details
 
Bulkhead connector viewed as if standing on engine facing windscreen;

bulkhead
  • Ignition to ACC
  • Switch at fast wipe – W/LG post = 12 v+
  • Switch at slow wipe – B/LG post = 12 v+
  • Switch in Intermittent and off  - K/LG post = 12 v+
  • Ignition to Off
  • Continuity between O LG and B LG posts in intermittent/flick and off modes only.
  • Ground pin to ground

The Motor to bulkhead connector is wired as follows:

motor