Attention Electrical Gurus, Need help with windshield washer wiring Options

[bbrock]

Right after ordering a complete Car Magic kit to convert my windshield washer to electric, I read Sir Andy's excellent tech article on the conversion. The idea of pulling power for the washer pump off the intermittent wiper feed so the washer is activated by pulling back on the wiper lever was too elegant not to try.

I happened to have this nifty vintage VW style splitter I bought some time ago for not other reason than I thought it might come in handy for some future custom wiring project. It was just the ticket for splitting off of my intermittent washer relay to power the washer pump.



After hooking everything up, I pulled back on the wiper lever and HUZZAH! The washers squirted and the wipers ran for two sweeps and parked. Pretty slick! I couldn't understand how the intermittent wipers would work when the lever was pulled down to turn the intermittent wipers on. I pull down on the lever to test them and nothing. As soon as I unplug the washer pump, the intermittent wipers start running. I'm not sure how the intermittent relay works, but thinking the timer is from charging a capacitor which then "bump starts" the wipers to run a single cycle.

Is there is a reasonably simple way to isolate the pump so it allows the intermittent mechanism to run without activating the washer pump? Could be a fun project. Or should I just go back to the original plan of installing the Car Magic switch? I just like the idea of minimizing the wiring.

[davep]

A very interesting discussion. I have been kicking this around in my head for years, but had other priorities. However, years ago I 3-D printed a switch mount to replace the water valve on the wiper switch assembly. This gave me the trigger for the pump. I believe the switch (a tiny momentary pushbutton) does not have the necessary current capacity, so an additional relay would be needed to actually power the pump. I also 3-D printed a disc to fit in the washer tank cap to allow the tank to vent; this allows us to use the regular 914/4 washer tank with just a simple and reversible modification. All I have left to do is figure out the wire lengths and route it. I could have 20 sets of these parts available.
http://www.914world.com/bbs2/index.php?sho...7916&st=29#

[bbrock]

A very interesting discussion. I have been kicking this around in my head for years, but had other priorities. However, years ago I 3-D printed a switch mount to replace the water valve on the wiper switch assembly. This gave me the trigger for the pump. I believe the switch (a tiny momentary pushbutton) does not have the necessary current capacity, so an additional relay would be needed to actually power the pump. I also 3-D printed a disc to fit in the washer tank cap to allow the tank to vent; this allows us to use the regular 914/4 washer tank with just a simple and reversible modification. All I have left to do is figure out the wire lengths and route it. I could have 20 sets of these parts available.
http://www.914world.com/bbs2/index.php?sho...7916&st=29#

I just realized I never posted a link to the CarMagic kit I keep mentioning in this thread. I added it in the first post starting the thread have added it here too. That kit sounds just like what you are describing, including he little disc to vent the bottle. I know several people have installed these and really like them.

I decided not to use it after reading SirAndy's tech article on adding an electric windshield pump. There I learned there is already an electrical switch inside the wiper switch assembly that can be used to trigger the pump. Even better is that most 914s already have a wire running from that switch to fuel compartment to trigger a relay when the wiper lever is pulled back. Figuring out how to get that to work with the optional intermittent wiper feature was a little tricky as the last four pages show.

The CarMagic kit requires too much drilling for my taste. This method only requires a single hole drilled to screw the pump to the chassis. The installation also doesn't require touching anything inside the cabin of the car except to pull or clip the water hoses from the switch valve, which I was able to do from under the dash. The rest is all done up front in the fuel tank compartment.

I'm kind of psychotic about wiring and making modification be as stealth as possible, so I used a little different approach for venting the bottle. I ran a drill down the small hole that is already in bottle cap and then drilled two small holes from the side into the channel created to turn it into a vented cap. Here you can see the drill bit sticking out the original hole and can just see it through one of the side holes.



I also left the tube from the cap to tire attached to the bottle to pay homage to the fantastically quirky pneumatic system that I regret having to replace. It's really there for the stealth effect, but does have a practical purpose in creating a tether for the bottle cap so it doesn't fall down into the fuel compartment when refilling the bottle. If I connected it to the spare tire, that hose also has a schrader valve in it that can be used to refill the spare without having to dig out you luggage and lift the frunk board. I'm not using that feature but might if I take a long trip with a frunk full of luggage. When everything is back together, this setup is completely stealth and looks like an ordinary spare tire powered washer system. Here's what my now electrified washer system using an unmodified stock wiper switch looks like. (IMG:style_emoticons/default/beerchug.gif)