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> Attention Electrical Gurus, Need help with windshield washer wiring
bbrock
post Jul 28 2022, 07:17 PM
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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.

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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.
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davep
post Aug 13 2022, 10:31 PM
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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#
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bbrock
post Aug 13 2022, 11:33 PM
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QUOTE(davep @ Aug 13 2022, 10:31 PM) *

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.

Attached Image

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)

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bbrock   Attention Electrical Gurus   Jul 28 2022, 07:17 PM
Spoke   @bbrock Do you have documentation describing the...   Jul 29 2022, 09:20 AM
bbrock   @[url=http://www.914world.com/bbs2/index.php?show...   Jul 29 2022, 10:04 AM
Superhawk996   Instead of the kit, I'm branching off the br...   Jul 31 2022, 01:46 PM
bbrock   Instead of the kit, I'm branching off the b...   Jul 31 2022, 01:51 PM
dr914@autoatlanta.com   intermittent is activated by pulling the stalk dow...   Jul 29 2022, 11:02 AM
FlacaProductions   As George says - but do you have the tab broken ou...   Jul 29 2022, 11:53 AM
bbrock   Let's back up a bit. My intermittent wipers w...   Jul 29 2022, 12:45 PM
lesorubcheek   It's kinda difficult looking at the wiring dia...   Jul 29 2022, 01:45 PM
bbrock   It's kinda difficult looking at the wiring di...   Jul 29 2022, 04:52 PM
lesorubcheek   I know the feeling. You just can't let this go...   Jul 29 2022, 07:47 PM
bbrock   I know the feeling. You just can't let this g...   Jul 29 2022, 10:52 PM
Spoke   I've been following this discussion but haven...   Jul 31 2022, 04:44 PM
bbrock   I've been following this discussion but haven...   Jul 31 2022, 05:09 PM
Spoke   Ah! There is something I should have explai...   Jul 31 2022, 06:10 PM
bbrock   [b]@[url=http://www.914world.com/bbs2/index.php?...   Jul 31 2022, 06:45 PM
Spoke   @bbrock I'm not sure how pulling back on the...   Jul 29 2022, 09:54 PM
bbrock   [b]@[url=http://www.914world.com/bbs2/index.php?s...   Jul 29 2022, 10:40 PM
bbrock   My previous post was incorrect. It was dark in th...   Jul 30 2022, 10:29 AM
Superhawk996   I apologize I'm worthless for this thread. Al...   Jul 30 2022, 10:36 AM
bbrock   I apologize I'm worthless for this thread. A...   Jul 30 2022, 11:20 AM
Superhawk996   I apologize I'm worthless for this thread. ...   Jul 30 2022, 11:38 AM
bbrock   Can you post a more comprehensive circuit diagra...   Jul 30 2022, 12:41 PM
Superhawk996   The circuit is so simple there is really no need...   Jul 30 2022, 01:18 PM
bbrock   The circuit is so simple there is really no nee...   Jul 30 2022, 03:51 PM
Bartlett 914   It has been awhile since I worked with the washer ...   Jul 30 2022, 01:08 PM
bbrock   I went ahead and ordered one of these low voltage ...   Jul 31 2022, 10:16 AM
Superhawk996   I went ahead and ordered one of these low voltage...   Jul 31 2022, 10:27 AM
windforfun   I went ahead and ordered one of these low voltag...   Jul 31 2022, 10:32 AM
bbrock   I went ahead and ordered one of these low voltag...   Jul 31 2022, 11:29 AM
Superhawk996   Here, I added the "complicated" part f...   Jul 31 2022, 11:43 AM
Superhawk996   @bbrock Do you actually have your intermittent r...   Jul 31 2022, 12:50 PM
bbrock   [b]@[url=http://www.914world.com/bbs2/index.php?s...   Jul 31 2022, 01:42 PM
Superhawk996   You're explanation of the grn/wht wire make...   Jul 31 2022, 01:58 PM
bbrock   [quote name='bbrock' post='3019478' date='Jul 31 ...   Jul 31 2022, 02:07 PM
bbrock   No -- that brown / black doesn't get ground t...   Jul 31 2022, 02:26 PM
lesorubcheek   Anyway, the DMM says this. Pull back the lever a...   Jul 31 2022, 02:54 PM
Superhawk996   just saw your other post Yes - the schematics are...   Jul 31 2022, 01:48 PM
bbrock   just saw your other post Yes - the schematics ar...   Jul 31 2022, 01:59 PM
bbrock   And I agree about the confusion. I'm not a fa...   Jul 31 2022, 02:09 PM
Superhawk996   I don't think you'll be able to get the co...   Jul 31 2022, 02:26 PM
bbrock   I don't think you'll be able to get the c...   Jul 31 2022, 02:31 PM
Superhawk996   :idea: Ok now I think I understand your idea bet...   Jul 31 2022, 02:58 PM
bbrock   :idea: Ok now I think I understand your idea be...   Jul 31 2022, 03:47 PM
Superhawk996   Now that I've had some time to think about the...   Jul 31 2022, 04:10 PM
bbrock   Now that I've had some time to think about th...   Jul 31 2022, 04:57 PM
Superhawk996   Don't think that one will work. It switches...   Jul 31 2022, 05:17 PM
Spoke   Now that I've had some time to think about t...   Jul 31 2022, 06:31 PM
bbrock   I think I agree with you about the switching. Th...   Jul 31 2022, 06:56 PM
Spoke   Yes, but the voltage readings are small. In the...   Jul 31 2022, 07:39 PM
bbrock   Yes, but the voltage readings are small. In th...   Jul 31 2022, 08:42 PM
Superhawk996   I shouldn't have called this a "simple...   Aug 1 2022, 06:38 AM
bbrock   I shouldn't have called this a "simple...   Aug 1 2022, 08:39 AM
Superhawk996   I still say we didn't need the full schematic...   Aug 1 2022, 09:03 AM
lesorubcheek   If the goal is to have an open circuit at S on the...   Aug 1 2022, 12:03 PM
Spoke   If the goal is to have an open circuit at S on th...   Aug 1 2022, 05:08 PM
bbrock   [quote name='lesorubcheek' post='3019726' date='A...   Aug 1 2022, 06:18 PM
lesorubcheek   [quote name='lesorubcheek' post='3019726' date='...   Aug 1 2022, 06:34 PM
bbrock   I did . . . just because that is the way I...   Aug 1 2022, 01:40 PM
Superhawk996   Here's the blurb from the 73' owner's ...   Aug 1 2022, 06:53 AM
bbrock   GENIUS! Dug through my spares and found an un...   Aug 1 2022, 06:55 PM
Spoke   Sounds like the intermittent relay needs a couple ...   Aug 2 2022, 03:50 AM
bbrock   Sounds like the intermittent relay needs a couple...   Aug 2 2022, 08:12 AM
Spoke   @bbrock Either BY880 diodes will work. According...   Aug 2 2022, 08:31 AM
bbrock   @[url=http://www.914world.com/bbs2/index.php?show...   Aug 2 2022, 10:55 AM
Superhawk996   Getting close. :trophy:   Aug 2 2022, 08:35 AM
bbrock   Unbelievable! The diodes arrived yesterday. ...   Aug 6 2022, 02:26 PM
bbrock   Well that escalated quickly :blink: The new VDO ...   Aug 13 2022, 07:44 PM
930cabman   [b]Well that escalated quickly :blink: The new ...   Aug 14 2022, 09:30 AM
bbrock   I may be able to piece together an original washe...   Aug 14 2022, 11:32 AM
FlacaProductions   Very cool - and everyone likes a graceful recovery...   Aug 13 2022, 10:29 PM
davep   A very interesting discussion. I have been kicking...   Aug 13 2022, 10:31 PM
bbrock   A very interesting discussion. I have been kickin...   Aug 13 2022, 11:33 PM
Superhawk996   :cool: Bookmarking this thread.   Aug 14 2022, 08:38 AM


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