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rear wiper not working..?

Hi -

The rear wiper on my '89 Capri 280 has stopped working; this is what I know;

I have checked behind the dash switch, and all appears ok.

I have taken a picture of the motor; sorry the quality is poor. Perhaps you can take a look at it so the following makes more sense;

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Two wires arrive at the motor, one black, one purple/black. There is

+12V on the purple/black. The picture shows a brown cable too; it looks like it's loose but it is firmly embedded in the body, and goes straight to earth just outside the picture.

As you can see, there is a diode between the black cable and a cable that goes to the top of the motor.

Here's the thing: when I bridge the purple/black and middle cable that goes to the top, the motor works. Even when I bridge it briefly, the motor does one full movement, then stops. When I bridge it permanently, the motor runs, but does not respond to the switch in the dash ( I can't switch off, in other words.)

I'm sure this makes sense to somebody cleverer than me...! Thanks for any advice.

Reply to
jaap
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The motor has an internal parking switch which has 'permanent' power to it

- ie not switched by the dash switch. Then there is the earth wire. The third is the switched supply. The diode is probably to sink the back EMF across the internal switch contacts to help prevent contact burning. They can also fail short circuit - test with a DVM set to ohms, it should show a low reading in one direction, open circuit the other.

Trouble is it could be German wiring doesn't follow the UK standard colours. But it should be easy enough to identify which is which by testing. To test the switch circuit rig up something like a stop light bulb - 20 watts or so. A DVM won't give an accurate indication as it doesn't draw any current.

Reply to
Dave Plowman (News)

Absolutely dead simple. I'll explain how it works.

OK, there are two positive feeds to the motor - a constant which allows the motor to return to the park position and a switched one.

The first goes through the nearside rear tailgate strut and is the constant +12v feed.

The second switched one, and the one at fault, goes through what looks like a boot light switch on the passenger side. THe passenger side plunger has a metal centre and the drivers side plunger is plastic.

If you look at the bottom of the bootlid frame on the passenger side, you'll see a 3/4" metal disc. This creates a contact with the "plunger" on the rear panel at the passenger side when the boot is shut and this is where the +12V from the dashboard switch goes to. If you trake it out, you can see the green wire, the same as at the back of the dashboard switch, hooked up to a spade connector on the bottom. In effect it turns the passenger side plunger into a connector. What happens is that both the top of the plunger and the metal disc in the tailgate frame get covered in crap or get surface rust on them. All you need to do is get some sandpaper and clean them up.

If you need a photo, reply to this and I'll do you one.

Reply to
Conor

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