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.

[Superhawk996]

(IMG:style_emoticons/default/idea.gif)

Ok now I think I understand your idea better. I'm used to thinking input is on the left side.

So this is what you meant?


So when you pull the stalk, you trigger the intermittent 12v input (S) to the relay.

Simultaneously the the wiper pump is on as long as 12v is present. Then when the black/brown returns to ground the pump stops, the wiper pump is decoupled, and the intermittent stays active. (IMG:style_emoticons/default/idea.gif)

Will be interesting to see if it indeed works.

But by the time you have to put that little gizmo in there I'm thinking we're back to an Arduino (in effect) (IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/laugh.gif)

But if it works as you propose . . . . we'll all owe you a beer

[bbrock]

(IMG:style_emoticons/default/idea.gif)

Ok now I think I understand your idea better. I'm used to thinking input is on the left side.

So this is what you meant?


So when you pull the stalk, you trigger the intermittent 12v input (S) to the relay.

Simultaneously the the wiper pump is on as long as 12v is present. Then when the black/brown returns to ground the pump stops, the wiper pump is decoupled, and the intermittent stays active. (IMG:style_emoticons/default/idea.gif)

Will be interesting to if it indeed works.

But by the time you have to put that little gizmo in there I'm thinking we're back to an Arduino (in effect) (IMG:style_emoticons/default/poke.gif) (IMG:style_emoticons/default/laugh.gif)

But if it works as you propose . . . . we'll all owe you a beer

Correct. It's all about opening and closing the relay that connects B+ to Out+ depending on what brwn/blk is doing on the B+ side. Where I could get screwed is if the sensor circuit of B+/B- allows current to flow to ground even when the relay is open. It shouldn't because the intended use case of the LVD is to disconnect a battery from its load if the voltage drops below a set threshold but we shall see.

Well, it is much simpler than an arduino on my end because I don't have to design and build the circuit around the arduino. I also don't think an arduino would work well here. If the arduino were powered by the brwn/blk wire, it would have to boot and load the sketch every time the washer lever was pulled. That would cause a significant delay. The alternative would be to power the arduino independently which is more wire, a more complicated circuit, and another potential failure point.

If this works, it is close to the original one-wire idea. I do have to add a short ground wire from B- to ground to read "battery" voltage, but you sort of have to do that to ground the pump anyway. I'll do that with a "Y" wire with a ring connector to attach to chassis ground at the pump mount, another with spade to plug into pump (-), and a bare end to clamp into the B- terminal on the LVD. Should still be very compact and tidy. Just please don't leak to ground! (IMG:style_emoticons/default/hands.gif) (IMG:style_emoticons/default/smile.gif)