The following applies to my '74 914. Other years may have
1. Start with the steering wheel. Remove the horn pad and remove the bolt & washer underneath the horn pad (use a 26mm or 27mm socket). Be sure to note the position of the steering wheel on the spline of the steering column. I used a pencil and marked the steering column shaft and a corresponding spot on the steering wheel. This will make for easy realignment when you reassemble the steering wheel. Slide the wheel off. For more information on steering wheel removal, see the Pelican Technical Article, "Steering Wheel Removal." For more information on removing some of the other parts of the steering column, see the Pelican Technical Article, "Replacing the 914 Ignition Switch."
2. Remove the dashboard knee pad. (There are bolts all along underneath and on each end. It will slide right out.
3. Underneath the steering column there is are two connectors for the steering column switches. Pull the connectors off carefully.
4. Underneath the steering column you will also find a hex head bolt inside a hole in the steering column. Remove that bolt.
5. There are four screws that hold the switches to the steering column. Remove those bolts. You should now be able to slide both switches out together.
6. On the old wiper switch, you will have the hoses connected for the pressure fed washing system. You can simply snip the old hoses. Mine were dry rotted and just broke off. I pulled the remaining house out of the steering column and out into the front trunk area (more later).
7. Now comes the tricky part. The wiring for both switch assemblies are clipped together with white plastic wire holders. I'll refer to these as the wiring harnesses. You can separate the two harness/assemblies quite easily. Also, you may find 4 metal sleeves that the 4 bolts that held the switches to the column went through. These also slide right out when you separate the two switches. Save them, you'll need them when you put them together again.
8. If you were to reassemble the new wiper switch and the old headlight/turn-signal switches together, it would not fit through the steering column as the new switch has a slightly wider wiring harness. Do accommodate the upgrade, you need to switch the white plastic wiring harnesses.
9. Take the old wiper switch and remove the wires from the white plastic wiring harness. Note their order and their respective positions in the harness. There is protective cap on the side of the harness where the wire leads come out. This is clipped on. You can easy remove it. The clip on mine broke because it was brittle, so I just epoxied it together when I was done.
10. Remove the wires from the white plastic wiring harness from the new switch and assemble the wires in the old wiring harness in the same order as before. Note: The colors are the same on both wiring harnesses. Note: You will have 2 extra wires. A red wire and a red and brown wire. Leave these off to the side for now. Reattach (or epoxy in my case) the old wiring harness protective cap.
12. Make sure the wires from the headlight/turn-signal switch are running through the wire separators on the bottom of that switch. (It makes for easy reassembly).
1. Align the switches in their correct order (wiper switch on bottom).
2. Clip the two white plastic wiring harnesses together.
3. Insert the metal sleeves in the holes of the wiper switch.
4. Slide the headlight/turn-signal switch on to the metal sleeves until the switches are one unit.
5. You should have an assembly that looks like what you took out of the car to begin with (with two extra wires)
6. At this point I clipped the metal connectors from the end of the two wires and attached 12 inch sections of red wire to each.
7. Now slide the switch assembly into the steering column.
8. I diverted the two red wires off to the left side, down the steering column where the hoses used to be, and pulled them out by the fuse block.
9. Secure the switches with the four retaining bolts.
10. Replace the allen-head screw under the column.
Inside the front trunk:
1. Remove the washer bottle using the screw mounted to the top of the wheel well. The bottle should pull right out.
2. There should be a fitting on the bottom with hose coming out.
3. Remove this fitting and plug the hole on the bottom of the bottle. (I used a small brass screw). If you want you can skip this and use this bottom fitting as the input feet for your washer pump! (An afterthought from my project).
4. Figure out where to mount the water pump on the washer bottle. You can either fit it on the bottom, or off to the right side near the vent blower motor. I placed the bottle back in the car, positioned the pump on top, and traced on the bottle where the pump was positioned so that it wouldn't interfere with any of the blower components or the closing of the hood.
5. Mounting the VDO pump was tricky. There may have been an easier way, but I couldn't figure it out. The mounting holes for the pump were between the pump motor and the pump frame. Accessing the mounting screws was impossible. I removed the four tiny hex bolts on the pump housing and the pump came apart and off of the pump frame. I then screwed the pump frame onto the washer bottle and reassembled the pump components onto the pump frame.
6. You now need to get fluid from inside the bottle to the pump. You've got several choices. You can attach the hose to the bottom of the bottle where the old pressure fed tube came from and the pump would suck from the bottom of the bottle. I chose to remove the tube from the bottle cap, drilled a hole through the cap and placed a hose down into the bottle.
7. Most of my tubing in my front area was pretty brittle. I chose to redo it. I also pulled the rest of the old tubing out from the steering column and removed it. I removed all the old tubing and simply connected the two washer jets to a T fitting (there was one in the existing plumbing) and then connected the T fitting to the pump.
8. My German pump had fluid "in" and "out" connectors, marked with a B and a D. The B connector goes to the washer bottle and the D connector goes to the pump. (If my memory is correct). An easy way to tell, is one connector has a little nub on the end and one is smooth. The smooth one goes to the bottle, and the nubbed one goes to the nozzles. Since the smooth side is the suction side, it doesn't need the little nub to hold the hose on. The nub keeps the hose on because the output is under a small amount of pressure.
9. Next you need to get power and ground to the pump. I ran two wires (one red and one black) through the grommet where the wires come from the steering column into the front trunk area and ran them over to the pump. I used insulated electrical connectors to connect wires to the pump power leads. I didn't want any sparks jumping in case of fluid leakage since we were very close to the fuel lines!
10. Connect all of the wires and hoses to the pump.
11. Slide the water bottle back in being sure not to crimp the hoses and resecure the mounting bolt.
12. Underneath the dashboard, you should now have four wires hanging (2 left over from the switch, and 2 that you just wired from the pump).
13. Connect the black wire that you ran from the pump to a suitable ground source under the dashboard. (You can save this step if you can find a suitable ground source over by the pump. I didn't want to drill an extra hole into the metal, and I really couldn't find a good ground).
14. Remove the fuse block by unscrewing the two mounting screws underneath. Connect one of the two leads from the wiper switch to the fuse block. I found a space over by the block that powers the wiper motor.
15. Connect the other lead from the wiper switch to the positive lead from the pump motor.
16. Reattach the fuse block and secure any loose wiring with cable ties.
1. Reattach the dashboard kneepad.
2. Secure the hornpad and horn wiring.
Now, when you use your wipers, you can simply pull the wiper switch, it'll power the little motor you connected, and shoot cleaning fluid onto your windshield.
My nozzles were improperly aimed and the pump was so powerful, it shot cleaning fluid over the car and onto the rear deck lid!
Karl has added the following:
I found out that if the pump runs dry, it needs to be primed again, otherwise it won't get any suction developed when the tank is refilled. Also it may be wise to add a one way valve to keep the lines from draining.
Pelican Technical Article:
914 Electric Windshield Washer Pump Conversion
Phillips screwdriver, metric Allen head wrench set, electrical crimes and connectors, 26mm or 27mm metric socket, pencil, metric hex head key set, metric socket and metric wrench set,
Porsche 914 (1970-76)
924 steering column windshield wiper switch, small VDO 12-volt water pump, 18-gauge wire (red and black), plastic tubing,T-connector
A clean windshield after using your electric windshield washing system
Replace your windshield wiper blades