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.

[bbrock]

My previous post was incorrect. It was dark in the garage when I tested voltage on S1 last night and I failed to notice I was reading mV rather than V. Looking at the circuit diagram again, it looks like S1 is not connected to anything in the J position, and connects to ground in any other position. This is apparently how the intermittent circuit is disabled because if I disconnect S1 (brown/black) wire from the intermittent relay, the intermittent wipers run with switch in the J position, and continue to run in the off position. It also explains why the wire is brown/black which confused me since brown is ground on these cars and brown/white is switched ground. Brown/black might mean it is both a switched ground and switched voltage?

When the lever is pulled back, with the switch in the 0 position, S1 is connected to 53a which is the 12v supply. It's hard for me to tell from the diagram, but I assume S1 is also disconnected from ground at the same time since it would create a dead short otherwise.

This is all starting to make sense now. When the washer pump is connected to S1, it gets 12v when the lever is pulled back and works fine. But when the lever is pulled down into the J position, the washer motor creates a path to ground which prevents the intermittent washers from activating. It seems what is needed is some kind of relay switch circuit so that the path on the S1 (brown/black) where to the washer pump remains open except when there is 12v present. Any ideas on what that circuit should be?