23 - Rear Wiper Intermittent

 On the right is the rear wiper electrical connector. On the newscionxb.com forum, Paul1114 posted that by adding a wire to position #4 and connecting it to the wire at position #3, the Low switch position activates the rear wiper just like the High switch position.

 By doing some additional testing, I found out that when the rear wiper switch is in the Low position:

• • ground was provided to the pin at position #4

  • jumping wires #2 and #3 together activated the rear wiper

  • when the jumper was removed the rear wiper parked

 Perfect! Now I needed to get a intermittent wiper (aka "wiper delay") module and add a wire contact to position #4.

 (To the right is Paul1114's picture, I added the numbers)

  A co-worker found this intermittent wiper module for me on eBay, it was $13 shipped. (Also on Amazon). It has an adjustable delay between 3-30 seconds via a rotary control which also incorporates an On/Off switch. When on, the module pulses the SPDT relay for about a half a second between delays. While the relay is active, the red LED illuminates. The wire connections for the green connector block from top to bottom are:

• • Normally Closed (NC) (relay not energized)

  • Common (COM)

  • Normally Open (NO) (relay is energized)

  • Ground

  • Power (+12v)

 If you've ever built your own desktop computer then these front panel electrical connectors should look familiar. When removed from their plastic casing, they happen to be a perfect fit for the blank socket at wire position #4, and make good contact with the pin in the Prius wiper switch.

  To help protect the intermittent wiper module I put it in a case. I couldn't find a case that I liked, so I hacked up a old plastic candy box to make my own case. I drilled holes to access the wire connections then secured the module and glued the top cover on.

Run 4 wires from the module and connect to the car wiring as follows:

• • NO taps into (but does not interrupt) #2

  • COM taps into (but does not interrupt) #3

(the above two connections act as a jumper, so NO to #3 and COM to #2 would work just as well)

• • +12v taps into (but does not interrupt) Ignition (the gray wire under the steering column)

  • Ground to #4 (the new orange wire in the picture)

(The connections in bold above are to the module.)

After this photo was taken, I insulated all the wires with electrical tape, then plugged the rear wiper connector back into the Prius wiper switch.

I tucked the intermittent wiper module up in a corner near where the hood release cable enters the engine firewall. I set it for the maximum delay of ~30 seconds.

It works great! When the rear wiper switch is on Low (- - -) the rear wiper sweeps once (then parks itself) about every 30 seconds. The High setting ( - ) runs the rear wiper continuously, just as it did before.