Wiper Motor Wiring

[The Rovering Member]

I bought a new pair of wiper blades & arms for my Oxford at The Enfield Pageant last weekend. The arms are slightly different to the originals being beefier with a larger spring owing to the general weediness of the originals which l have always found pretty inadequate on the Farina's l have owned. They fit well with a good sweep & very effective water clearance but l am finding that they stop once the worst of the water has gone which is obviously the stronger springs fighting the perhaps tired motor. Fold the wipers back & away they go:



In the hope of a general improvement of the system, I do have these on the shelf. I bought the square one in a Rover box but as yet haven't found a Rover that it fits, nevertheless it looks as if it could be mounted in the Oxford with a suitable bracket to hold it to the bulkhead. It might be a two-speed too:



It shows every sign of being NOS or factory reconditioned but trying to bench test the motor l've had no sign of life as yet. As far as l can see from some t'internet searching of the Lucas units, the green is normally a permanent live so as to power the park function after switch-off, the earth cable also supply's the park switch, not sure why it needs it's own earth cable as the casing & cable are connected, the main earth being the casing. Then the other two connections are the fast & slow speeds (unless it's a single speed unit & one is for the park switch) which supposedly are switchable live wires & the switch apparently grounds the connections though l'm not sure how that would work. Surely the switch should supply the live feed rather than one already being there & then earth through the motor & casing.

So far l've deduced that whichever coloured cable is connected to live also energises the other two but if that's the way it's wired you can't directly ground them as that's a dead short so how is the circuit completed to power the motor, which hasn't even coughed yet? Do the three live wires signify a fault in the circuitry or have l got it completely wrong?

Simply earthing the case/black wire & connecting live to any of the colour cables does nothing.

 

[GWEN1974]

Hi,
Neither of those wiper motors look like a P6 unit. However, on the basis that Lucas motors or their equivalent worked with similar wiring, I have attached an as existing wiring diagram that I drew up for my P6 (in full technicolour) when I was converting it to a VW 99 relay to get a variable electronic intermittent function. The wiper switch bridges different contacts to achieve the required speed.
Also attached are diagrams that I downloaded from a previous posing. Hope this helps.

 

[colnerov]

Hi, Two things I've learnt over time, switched earth is gentler on the switch because the load takes the initial shock, which is why horns used to be switched earth. One of the differences between the square and round wiper motors, round ones have permanent magnet field and square ones are electromagnet hence why there are more wires. I found this out years ago when trying to use one to reverse direction (for a can't remember project) and only reversing polarity of one set makes big sparks. I can't be helpful with wiring it up because it was too long ago.

Sorry I can't be more vague.

Colin

 

[arthuy]

Square one is probably a P5 unit.

There is an integral park and and fancy stop and and park off screen movement.

I will have a look for a diagram.

 

[arthuy]

Have a read over this. There is a diagram and colour codes.

P5 wiper diagram

 

[The Rovering Member]

No it's not P6 & apparently not P4 or P5 either according to Phil (Nottingham) Jones. MK2/3& P5B motor from Wadhams has the mounting lugs in the wrong place & five wires. Mk1/1a has the drive mechanism mounted vertically:



Though l was sitting next to my Saloon while looking at the motor & didn't think to compare.
John Wallet does mention that they're difficult to bench test in the P5 club thread, l might have to drop him a message.

I bought it years ago because it was in a Rover box & cheap probably assuming it was P5 but it was very likely an excellent buy as NOS & reconned motors are pretty expensive now & there must be a way to get it functioning in the Oxford.
The other one looks somewhat like the P6B motor but is also similar to the Marina ones. It has Rover written on it in marker pen but whatever it is l doubt l paid much for it.

Thanks for the diagrams.

 

[arthuy]

Could be a series landrover, lot of cars used lucas parts back in the day.

If you keep Goolgling you might get lucky.

 

[colnerov]

Hi, If you take the cover off the gearbox and find the number on the gearwheel which is the angle of sweep for the wipers, this may help you confirm or deny any options for it's application.

Colin