FJOVA Posted June 12 Share Posted June 12 (edited) I am working on a 1972 240z (build date 11/71) with my son and we have hit a small snag with the combination switch. Everything about the switch is working well except the washer motor wiring. I press the button and nothing happens. Now, I know the pump works as it is new and I have tested it with a 12v battery. I have also tested the all wires on the switch, both on the connector and an additional blue/white wire that resides outside the connector and is currently unconnected. As it turns out, this blue/white wire that is outside the connector is the one that goes to 12v when the washer button is pressed (see pics with wire circled). I have no clue where it should be connected as there is no obvious connection point. BTW, the switch is unmolested, was fully reconditioned and works well. The car came to us largely as an unassembled project and we have made excellent progress to this point. I am sure I am missing some connection point for this wire but it is not obvious where to connect it. Any help is appreciated. Thanks. Edited June 12 by FJOVA clarity 1 Quote Link to comment Share on other sites More sharing options...
Mitchel0407 Posted June 15 Share Posted June 15 Try and see if you can find a wiring diagram online. Unfortunately I only have one of a 197 280z which I will upload just in case as I suspect not much has been changed regarding something like the washer motor over those years. Try and follow the wiring with a multi meter and see where the power stops once you press the button. Also try and check the fuses, one might be blown or has a bad connection. It might be a stupid tip but try and activate the washer with the ignition switch in different positions. I was once lead down a rabbit hole thinking my blinkers weren’t working while in fact I needed to turn the ignition switch all the way to the on position (accessory position didn’t work). N77ZCAR-WIRING.pdf Quote Link to comment Share on other sites More sharing options...
jhm Posted June 16 Share Posted June 16 Anyone wanting free FSM downloads for their S30, they're available free for all production years at: https://www.xenonzcar.com/s30/fsm.php This website also carries good reference data for other-year Z cars. @FJOVA, I took a quick look at the Body Electrical sections for several years; and could not find a definitive answer to your specific question....sorry. It may be worth posting up on ClassicZCars.com, as they have a big following of folks doing original restorations. Good luck with the rest of the project!! 👍 Quote Link to comment Share on other sites More sharing options...
FJOVA Posted June 18 Author Share Posted June 18 (edited) Thx for the comments. I have tested the switch and harness connection points and all is working as it should from what I can tell. I did install the honda wiper motor swap with relay so that might be causing part of the issue. However, the fact that the blue line goes to 12V when the button is pushed is still an enigma. I believe the wire should connect somewhere but it is not clear on my harness. I have replaced both the dash (used in great condition) and engine (new) harnesses along with the fuse panel to blade type so it could be a mismatch of parts that is creating the issue. For now, I intend to run the blue wire directly to the washer motor so I will at least have washer capability even if I have to manually activate the wipers. Edited June 18 by FJOVA clarity 1 Quote Link to comment Share on other sites More sharing options...
FJOVA Posted June 24 Author Share Posted June 24 I found the wire. The black with yellow stripe comes in on the turn signal side of the switch (see picture, blue arrow pointing to the wire). I had the ground connected there. That ground, which is on the turn signal side, connects to the ground on the combination side of the switch (see picture, red arrow pointing to the wires). After that all was good. I wondered why the circuit seemed to work fine with my crossed wiring of the black to black/yellow. As it turns out the switch was finding ground through the wiper motor. As I was tracing the wires for the second time, I disconnected the wires at the wiper motor and found my headlight would go out... Eureka! Problem is now solved. Thanks again ! 2 Quote Link to comment Share on other sites More sharing options...
Mitchel0407 Posted June 24 Share Posted June 24 Great to hear that you found the problem! I had a similar problem when upgrading my dashboard backlighting to LED. I knew that they alle worked but after reinstalling the dashboard into the car and testing everything out only the tachometer backlighting didn’t work. Turns out that the connections to the backlight had reversed polarity. After switching the two pins around in the connector everything worked perfectly. This wouldn’t be a problem for incandescent bulbs but seeing as LED’s are diodes the switched polarity suddenly did become a problem. Quote Link to comment Share on other sites More sharing options...
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