Beginner Electrical Questions

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I hope that was just an elderly fuse! The diagram is based on info from a really useful Lightweight site
http://www.land-rover-lightweight.co.uk/ but re-drawn for a simple SPDT switch.
Hopefully self-explanatory, but the only thing to be aware of is that the park switch shorts the NLG wire to ground when the wipers are parked. This is to make the motor stop immediately and not just grind to a halt. But it means some care is needed when testing - best to disconnect the NLG wire while running a feed direct to the RLG. Who knew wiper wiring could be so complicated!
Wiper Wiring SPDT.jpg
 
That pin diagram matches where I've got wires going into the motor so that's good. I definitely only gave it G and RLG when I tested it, nothing on NLG.

I don't fully understand the park switch operation if I'm honest. Can you help me?

- The G switched ignition feed should always be live whether the wiper switch is on or off, is that right?
- When my wiper switch is off neither NLG or RLG should be live going into the motor?
- When my wiper switch is on the RLG should be live going into the motor, but NLG would never actually be live going into the motor as it's just there to complete a circuit with RLG _inside_ the motor when in "park" mode?
 
Here's how it works:
  • when the wiper switch is ON, power goes from the green wire on the ON side of the wiper switch to the RLG wire that drives the motor. The park switch circuit doesn't do anything while the wiper switch is ON.
  • when the wiper switch is turned OFF, power goes from the green wire on the park switch (terminal 4) through the park switch and out on the NLG wire from terminal 2 to the OFF side of the wiper switch and from there to the RLG wire to the motor. The motor continues to run until the wipers reach park position, when the park switch cuts off the power.
Both green wires are always live with ignition on, but the park switch circuit doesn't actually do anything useful until the wipers are switched OFF.
scottonthefen said:
When my wiper switch is on the RLG should be live going into the motor, but NLG would never actually be live going into the motor as it's just there to complete a circuit with RLG _inside_ the motor when in "park" mode?
Click to expand...
The park circuit is completed outside the motor through the OFF side of the wiper switch. The way to understand this is to see the NLG wire as an output from the motor that is live while the wipers are not parked.

Thinking about your blown fuse, it's possible the wiper linkage is binding and making the motor draw excessive current. If the fuse blows again, try taking the linkage off the motor - if it runs ok without the linkage then you know there's a problem in the linkage somewhere...
 
ExMil109 said:
Here's how it works:
The park circuit is completed outside the motor through the OFF side of the wiper switch. The way to understand this is to see the NLG wire as an output from the motor that is live while the wipers are not parked.
Click to expand...
Got it, cheers.

ExMil109 said:
Thinking about your blown fuse, it's possible the wiper linkage is binding and making the motor draw excessive current. If the fuse blows again, try taking the linkage off the motor - if it runs ok without the linkage then you know there's a problem in the linkage somewhere...
Click to expand...
While it was out I greased it all up and also the wiper drive wheels so they were free enough to turn with my finger. But as you say if my fuse does keep blowing I'll take the motor out and test it on the bench.
 
Thanks for all the help. I finally got the new wiper motor in, the earth at the wiper socket re-crimped after it broke, and a wiper switch that connects the right wires for auto-park and always on - and my wipers now work so thanks! :)
 
Yes it is! Next jobs are front crank seal, water pump, and that panel lights switch to re-wire.. plus whatever welding I can fit in while the weather's good for it on the driveway!
 
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