Wiper motor and rear lights wiring

[Captain Mike]

Hi all
I am on the electrics now in fixing problems with my Ruby and have the wiper motor out because it would not work, I have checked to see if power was going to the unit before removing it and now have it on the bench with a 6 volt battery for testing, I think I may have had the wires crossed going to the terminals of the wiper from the battery, Question; is the motor or other on the wiper motor polarity sensitive ?

Additionally I have issues with the rear lights, I can get the brake lights to work but not the rear lights and brake lights together, I have one live wire going to the pork pie light and then going to the rear lights but the pork pie light has two bulbs in it, not sure how this all should be wired between the pork pie light two bulbs and the rear running lights and brake lights, looked at a few wiring diagrams but not sure how the the three lights work together any help will be appreciated 

Thanks
Mike

[Tony Griffiths]

A useful start is to click on the Ruby wiring schematic that can be found here. Download and get it printed A3: https://aus7in.wordpress.com/da7cwiring/
If you don't know this (and as everybody on the forum will advise) a really good earth is a tremendous help on a 6-volt system. I understand that, if you can run a cable direct from the battery's negative terminal to a point under the back seat and link all the lights to that, it's a great help.

[Dave Mann]

Look on rear axel removal Mike I've entered the wiper motor answer there by mistake

[Captain Mike]

Thanks both much appreciated, I have the wiring diagram already down loaded but still cannot make the brake lights work with the tail lights, the earth from the battery is a good idea Tony and thanks Dave for the info on the wiper motor

I will battle on with the real lights and brake lights it must be something simple that I am missing as always
Cheers
Mike

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Hi Looking at the wiring diagram on the link it seems there is only one stop light and one rear light am I missing something ?

Cheers 

Mike

[daveg]

Mike,
The cars were originally only fitted with one rear light but most people now fit two. To keep things simple concentrate on just one
lamp and when that is working the two can be connected together.

You should have have 3 connections to the rear light:-

1) A supply via the lighting switch to the side light
2) A supply via the brake light switch to the brake light.
3) An earth supply, this maybe a separate wire or a connection via the bodywork.

Does this match what you have got?

Dave

[Dave Mann]

I should have explained that the MT7 pull & spin iis not self starting you have to spin it clockwise to get it going.

[Captain Mike]

Hi Dave
Thanks for the help, I have one power supply to the rear lights, I am thinking I should have two, this is why I can have either rear lights or brake lights not both
Cheers 
Mikee

["Slack Alice" Simon]

Don't rely on bodywork for electrical connections.

Run an earth from the battery to each light, or as in my case, an earth wire from the battery to the offside (if closest to the battery) light, then to the centre number plate light, then across to the nearside light.

[John Cornforth]

Hi Captain Mike

As the author of the Dorset club's diagram, maybe I can shed some light (sorry). I chose to draw the circuit as the car was supplied, because if I started to include modifications then where would I stop ?

Originally, the single rear "porkpie" light housed one stop lamp and one tail lamp. The stop lamp has a wire which starts at the brake light switch under the driver's floor. The tail light has a red wire which starts at the PLC2 Lighting/Charging switch. There is a common earth to the bodywork, and because the spare wheel cover is removable this earth has to take the form of a physical wire (loomed with the other two) which connects to the bodywork at the rear. I have no information on exactly how this was done originally, but logically it would be in the lower area of the spare wheel well.

Austin, in common with nearly all car manufacturers, used the body for earth returns and there is nothing wrong with this in principle. Over the years various joints (e.g. from headlamp body to wing and wing to car) may corrode etc, and some owners have gone down the workaround route by adding earth wires either to bridge joints in the bodywork or even all the way back to the battery. I accept that in some circumstances this may be the pragmatic option, but body earthing can be made to work given good joints.

Some time later the law changed to require two tail lights. I believe this law was (unusually) retrospective, so many cars would have had tail lights added to the rear wings. Some owners would have gone further and fitted dual tail/brake lights. Some owners would have kept the pork pie working, others not. The wiring joints and routes were up to the individual. Most lights would have been designed to earth to the rear wing on which they were mounted, and rely on the wing being connected to the rest of the body by its mounting bolts.

In summary, there is no one "official" way of doing this. My preference would be to splice into the loom to the pork pie at some weather sheltered point low down in the spare wheel housing, and thoroughly tape over the splice. If you are running wires for tail and brake to wing mounted lights, it's no real hardship to include a third (local earth) wire each side and run these back to share the earth point for the pork pie, or something similar.

Finally, I have no details of how Austin connected the body earth back to the engine block/starter where the thick battery return connects. I suspect earthing was initially via the solid engine mounts, and later via the copper petrol pipe from the tank. Alternatively, there may have been a mid point "tee" connection via a lug between the battery return and the front of the battery box. These details seem to have been lost over the years. With the higher wattage bulbs that many now fit, I recommend adding a decent size braid strap somewhere between the body and the engine block

[Captain Mike]

Thanks for the info John

My car is a 1935 Ruby so has both brake and running lights on the back wings along with the pork pie light, this explains things better, I will report back what the solution was

Cheers
Mike