Intermittent wiper switch

[Ian]

Hi all,

I'm in the process of fitting an combined wiper control switch that does on/off/intermittent (and wash too), the same as fitted in this recent article viewtopic.php?f=14&t=8311. It's a Cole Hersee 75602-04
However I am trying to wire it to the original pinz 4 wire wiper motor. I'm having trouble getting it to work properly and wondered if anyone else has done the same job and could share the wiring method, or knows if it is even possible or not?
The switch will do 2 speed wipers and I know I aren't going to get two speeds, I'm just wiring into the low speed wire on the switch.
I can get the wipers working with it, but not parking properly. When the points in the motor open, it breaks the power, but the inertia built up is keeping the wipers moving and then the points close and it powers up again. And so the cycle repeats. Therefore the wipers basically won't switch off!
I have discovered that if the screen is dry, the drag of the blades will cause it to cut out and the wipers stop before the points roll over and the intermittent/on/off functions normally. Not if the screen is wet though which is of course when I need them to work
Any help appreciated, cheers, Ian.

[Ian]

Obviously not a popular mod. Just to update, with the addition of a changeover relay and a diode this is now working.

[TechMOGogy]

Thanks for the update
Do you have details of where/how you wired the relay and diode?

[Ian]

I've attached a wiring sketch which will hopefully show up below..
Basically I worked out that the new switch will not short the 31 and 31b terminal on the motor when you turn it off which is why they wouldn't park. After a lot of head scratching and experimenting I came up with the double pole relay idea in the sketch. This initially didn't work either and I then worked out it was back feeding via the 53 terminal. I fitted the diode and it worked better than it ever has done and they park perfectly ever time now.
It is good having the main on/off control, intermittent and power wash all on one switch. With a bit of work I did manage to get the switch into the standard panel along with the original bulky light switch, but it isn't in the original hole.
Since doing the install I have wondered what would have happened if I'd just fitted the diode into the wiring without the addition of the relay. Now its in I'm unlikely to bother trying, but if anyone is having a go, I'd perhaps try it with just a diode, may work...