Author Topic: How-to: floor-mounted wiper mist button  (Read 5392 times)

Offline rich weyand

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How-to: floor-mounted wiper mist button
« on: November 18, 2013, 03:14:59 PM »
OK, so reaching for the wipers on the dash is a pain in the butt, and an intermittent/delay module only makes that a bit easier.  Instead, I rigged a pushbutton on the floor.  It runs the wipers in LOW as long as you hold it down, then the wipers will park when you release.  You can get one swipe, two, whatever, whenever you push the button.

Here is the mod in pix:







OK, here's how you do it.

1) Get a momentary floor switch from US Communications, which makes undercover police radio gear.  They have a floor-mounted push-to-talk button that they make by remanufacturing GM headlight dimmer switches.  Cost me $38 plus $6.89 postage via Paypal.  Email disguisedantennas@gmail.com to order and for payment information.  They shipped it the same day I ordered it.  This is the only momentary switch I found that is actually designed for auto use and to take serious use.

2) Remove the standard headlight dimmer switch, rotate it 180 degrees, and remount it.  This clears the spot for the new switch.  You can see the old footprint of the standard switch in the photos if you look.

3) Mount the new switch to the left and slightly below the existing one.  There is a flat spot in the floor there.  Just use duplicate hardware as what is on the existing switch.

4) Remove the upper steering column cover (four screws, two on either side of the column), the headlight switch knob (release pin on the side of the switch body under the dash), the radio knobs (pull off), and the instrument bezel (eight screws).

5) Remove the W/S wiper/washer switch (two screws) and unplug the connector.

6) Terminate two 16 AWG wires with spade connector females and connect them to the new floor switch, run the wires up behind the dash and out the W/S wiper/washer switch hole.

7) Locate the "B" and "C" wires on the connector.  These are the second and third up from the bottom, and are the "OFF" and "LOW" positions.  They should be BLK/LT BLU and GRY.  See http://www.73-87chevytrucks.com/techinfo/wiring_diagrams/77-80_cab_inter.jpg.  Strip a small length of each wire about an inch back from the connector.  Solder the wires from the switch to these two wires (no polarity issue) and wrap them separately.

8) Turn on the ignition and test switch operation.  The wipers whould run as long as the switch is held down, then park when it is released.

9) Cut a hole in the carpet for the switch to poke up through.

10) Reconnect and remount the W/S washer/wiper switch and replace all instrument panel parts.

Note: this mod will also work if you have the intermittent/delay module.  The correct wires are on the back of the module, not the switch.

Why does this work?  What you are doing with the switch is connecting the wiper motor LOW speed lead to ground, engaging the motor in LOW.  After you release the switch, the parking cam will take the wipers back to their park position.  These two leads on the switch (OFF and LOW) are the ones that connect to the parking cam on the motor, so in essence you are convincing the motor it isn't parked when it is.

The reason you have to use the OFF position of the switch and not just connect LOW to ground is so that the switch will be disabled when the wipers are in HIGH, so that both speed wires won't be grounded at the same time.
Rich

"Working Girl": 1978 K-10 RCSB 350/TH350/NP203 +2/+3 Tuff Country lift