Fitting a Defender Rear Wiper onto a SII SW?

[TJRL]

I am looking to fit a Defender rear door wiper onto my 1960 SII, but I need a bit of help with the wiring up. The Defender wiper motor has two connector blocks, one with 2 terminals and the other with 3 terminals.

So far I have found that by wiring the 2 terminal block with one terminal getting a positive feed via a simple wiper switch and the other terminal being earthed to the door the wiper operates and stops as soon as the switch is turned (off without parking the wiper).

Like this the 3 terminal block is not used but I think if it was then the wiper would self park, if I could just work out what each terminal should be connected to!!

As my vehicle is 53 years old, the Defender wiring diagrams I have looked at have not helped me to work out what the five connections on the rear wiper should be.

Has anyone done this or know how I should proceed, any advice grateful received.

[Jon White]

Yes I've done it but can't remember the wiring, but in short all I did was looked at the defender wiring diagram and worked it out from there.

Iirc there is a live feed ( switched ignition) that loops in and out of the park switch connection (the two pin connection) into the 3 pin plug. The other two connections into the three pin are earth, and the switched live from your rear wiper switch.

As I say that's all from memory but check the defender wiring diagram it's pretty simple.....

Jon

[TJRL]

Thanks Jon, in fact I have advised by AutoSparks that switched lives is a sort of "wiring no no" as it can lead to fires behind the dash, so it is best practice to switch the earth instead.

Anyway following Jon's advice here is the Defender wiring diagram and details below of how I got it to work:-

With a 5 pole relay added, the wiring is:-

Wiper
CO388-1- Connects to earth
C0338-2 - Connects to relay C0124-2 (common out)

C1105-1 - Connects to relay C1024-5
C1105-2 - Permanent fused live feed
C1105-3 - Connects to earth

Relay
C0124-2 - To wiper C0338-2
C0124-4 - To wiper switch (to earth when wipers are switched on)
C0124-5 - To wiper C1105-1
C0124-6 - Permanent fused live feed
C0124-8 - Permanent fused live feed

So when the wipers are switched on, the relay triggers and power flows via C0234-8 to C0124-2 and so to the wiper motor C0388-2.

When the wipers are switched off the relay drops but power can flow via C1105-2 to C1105-1 to C0124-5 to C0124-2 and so to the wiper motor C0388-2 until the park switch disconnects C1105-2 from C1105-1.

Hope this helps others and thanks again to Jon.

[Snagger]

The system works with the use of a rotary dash switch with tree terminals. What happens is that the switch will feed power to an initial trigger input terminal on the three-pin motor block to move the motor out of the park position. The park switch is then thrown and then needs a feed to the park side of the switch to continue feeding the motor. In other words, the motor is only powered by the dash switch while it's in the bottom of the sweep, the rest of the time it's powered by the park switch. The park switch power is cut when the wiper reaches the bottom of the sweep, obviously, so with the dash switch off, the motor will cut out.

The power flow when fully installed will go to the motor 3-pin switch block, back through the dash switch, and then to the motor 2-pi block. One of the 2-pin block terminals is the motor earth. I can't remember if it's polarity sensitive, but jumping the motor as you did will show that.

To work out which is terminal does what, try a continuity check across the 3-pin block terminals and see which pins allow current with the motor in the park position and again anywhere in the sweep arc (by jumping the motor via the 2-pin plug). The terminal that always has a connection to one of the other two is the feed terminal from the fuse box. Note down the conditions under which the other two terminals connect to it, so you know which provides a live output in park and which in sweep.

Now do the same test on the rotary switch. The terminal that is always connected to another will connect to the feed side of the 2-pin motor block. The other two terminals will be connected to the outputs from the 3-pin block. The 3-pin terminal that is live with the motor parked should connect to the switch terminal that connects to the switch output with the switch "on". The 3-pin terminal that is live with the motor in a sweep position should be connected to the switch terminal that connects to the switch output when "off".