My car's PO had handled the problem of a non-functioning windshield washer pump by adding an electric one, and connecting it to an aftermarket momentary switch he mounted next to the ash tray.
Since I believe functions should be controlled by as few switches as possible and the original wiper/washer switch is already set up to provide both functions, I thought I'd try to fix the original. I removed the back of the pump and after analyzing the wear, realized even if I did get it working, it would never be reliable. It was definitely designed as a throw-away part.
I suspect there are others here in the same situation. I was only able to locate 2 sources for replacement windshield switch/washer combination knobs that are even close to the original... Neither are exact, both are electric and both cost about a gazillion dollars.
I came up with option "C", and if you don't want to spend the money or get away from using original equipment, I'll show you how to electrify your old switch so all of it's functions work and it still maintains a bit of the squishy, deeply satisfying feeling of pumping water with your thumb.
If you just said "Yes", just follow these simple, no technical know-how needed, steps:
1. Remove your windshield washer pump. The PO had removed mine many times. The plastic threads holding it to the dash are pretty much shot, so I'll be epoxying mine in place after the car is together and everything is settled.
2. I don't have a picture of the original pump's back, but the back end is a press-fit white piece with 2 hose connectors coming out of it. With a knife screwdriver, Dremel or brute force, worry or cut the white piece out of the housing. Don't worry about destroying it, we won't be using it again. Try not to mess up the end of the housing however.
3. Once the white piece is out, remove the rubber water chamber if its still attached to the switch. Inside the switch you'll see the end of the nylon shaft terminating in a large ball that use to compress the water chamber. We'll use the ball to push the button of an electric momentary switch.
4. Sorry I don't have pictures of the next steps, but I'll try to explain as best as I can... You'll need a standard 12 volt mini flood light bulb - the type of connector doesn't matter. It also doesn't matter if its incandescent or LED. Incandescents burn out more often than LEDs, so if you can find a dead incandescent, use that.
5. We only want the bulb's plastic reflector, so carefully remove, or go rogue and break the glass lens (being careful not to cut yourself, of course). Also, remove the bulb and the part that connects it to the power source. You should be left with nothing but the plastic silver reflector.
6. Pick up a momentary push button switch large enough to handle the load of your pump. It'll need to be the type with a 1/2" hole mount. The PO had wired a suitable remote starter inside my engine compartment, which I'll be replacing with a more water resistant one. But the momentary switch he chose is perfect for this task as well. The button of my switch moves about 3/16" and with about the same amount of resistance the old washer pump had.
7. Using a razor knife, scrape the center hole of your bulb reflector until it snuggly fits your momentary switch. Next, nip half a dozen slots, about 1/4" long around the outside edge of the reflector. Sorry I didn't take photos of this step, but the switch is already installed and I'm not pulling it apart... Sorry. The reflector should look like a flower, if that helps you to visualize what I'm describing.
The outside diameter of the reflector is slightly larger than the inside diameter of your washer's housing. The slots around the reflector allow the plastic to flex and snap into the same retainer groove that held the original white piece.
8. You'll need to determine how deep your momentary switch needs to sit inside the housing and how much movement your original pump knob requires to close the switch's contacts. I held the parts together in one hand with my voltmeter clipped to the switch's contacts, and pressed the Europa's knob with my other hand. When everything tested with the best action and feel, I noted the position of the switch's edge in relation to the end of the housing.
9. After you settle on how deep the momentary switch must be inside the housing, snap the reflector into place and measure how deep the 1/2" hole goes into the housing. Without the switch in place, the reflector can be worked back out without harming it. Calculate how far the switch needs to go into the reflector, locate it and lock the reflector in position using the switch's mounting nuts. It might be a good idea to put a drop of superglue on the lock nuts... Just in case.
10. Now press your reflector, with the switch attached into the housing. The "fingers" you created around the edge will flex and snap into the groove, locking your new momentary switch into place. Now the only thing left for you to do is to hook your new switch up to your windshield washer pump's wireing. The tactile feel of pressing the knob is close to the original setup and the contacts for the 2 speed wipers haven't been touched and will work as they always have. Of course, you won't be able to control the pressure, but we all know it's better to use as much pressure as possible so you can flood your competitors' windshields while you clean your own
Enjoy. I hope at least one person can put this to good use.
Bruce