410 Wiper Motor Wiring

[DODD]

Hi Roger,

You are correct that the connection to terminal 5 will only give a 2/3rd wipe but the arch of the wipers is sufficient to completely clear the driver’s view but not all of the passenger’s side of the windscreen.

To operate the wipers via the toggle switch, you have to give the switch a reasonably quick press. The reason for this is if the press is too quick the wipers will move slightly further into park position and not travel across the screen.

Irrespective of whether the wipers have been operated via the main switch or the toggle switch in any sequence, operating the toggle switch will always move the wipers further to the park position, albeit only by a fraction before moving across the screen.

When I initially checked if Thomas’s proposal would work on my 410, I used a test wire with a 5amp inline fuse just in case the 410 was different to the 411. I decided to keep the 5amp inline fuse in the final wiring as a safety measure.

All in all, I am very pleased with the performance of the addition and I still have the option of using the main on/off switch for a single wipe if required but if you can see an alternative sequence for wiring the momentary switch into the circuit, I will be happy to try it out, as it’s a very simple procedure to swap the wires around near the motor.

Brian

[DODD]

Roger,

I should have mentioned in my previous posting that since I have owned my 410, when turning on the wipers, I always get a 2/3rds wipe, before a full sweep of the windscreen.

So, when I want an intermittent wipe using the on/off switch, I have to pause over the switch until the 2/3rd wipe has completed its cycle; this is then followed by a full sweep of the wipers. Because of the delay I usually accept a 2/3rd sweep, which I find is sufficient.

I don’t know if this is a common problem to other 410’s or one peculiar to my car; it’s possible that prior to my ownership, someone has transposed one of the wires, whilst working on the car.

Brian

[Roger Morrall]

I’ve been thinking about this and am well on my way to writing a thesis on the Lucas 6 Watt and 16 Watt wiper motors that were used on the 410s and 411s respectively.

Brian - Your 410 wiper motor is behaving exactly as I’d expect it to, I don’t think any previous owner has changed anything. You are bypassing the limit switch when you ground terminal 5. The limit switch goes to ground anyway and opens in order to stop the motor when the wipers have reached the park position. So bypassing it means that you are causing the motor to run on slightly beyond the park position before it then then starts the next sweep. You have to keep your finger on the switch that you are using to ground terminal 5 for long enough allow the limit switch to close again to allow the sweep to continue. You are quite safe in grounding terminal 5 because that is only ever connected to earth via the limit switch. THIS IS NOT TRUE OF THE 411 WHERE TERMINAL 5 CAN BE LIVE IN A NUMBER OF CIRCUMSTANCES- the 411 motor and it’s wiring and it’s switching logic is entirely different to the 410s

The change between the wiper operating arc and the wiper parking arc is achieved by 1) a degree of play engineered into the crank arm that drives the rack that runs to the wiper wheel boxes 2) reversing the motor so that then drives the wipers in a different arc. Each motor reversal between slow-to-stop and stop-to-slow has to take up this play which is why you get the 2/3rds wipe before the wipers then take up the full wipe pattern and also the 2/3rds wipe before they shut down

You could perhaps build a timer and a relay into your circuit to give a timed operation of the wiper off a single tap on your momentary toggle switch

[DODD]

Roger,

Many thanks for your detailed explanation.

I like the idea of the timer, if I install the timer I will still only get a 2/3rds wipe on each movement across the windscreen using terminal 5 but I intend to install one anyway. I will replace my existing single pole momentary switch with a double pole. This will allow me to have a single 2/3rds wipe on one action of the switch or say 3No. 2/3rds wipes on the other action, according to how long the timer is set.

I have sourced the switch and a time delay relay which should be with me tomorrow.

Brian

[Roger Morrall]

Good thinking - I think most time delay relays give you a live output as opposed to an isolated contact so you’ll perhaps need to take that output to a relay to switch your earth. Does that make sense?