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Wipers functions using a DPDT switch

Practical Motorsport Wiring - Club Level

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Hi guys, as per my previous posts I'm in the process of designing a custom chassis harness for my trackday / race car. My last circuit is the wipers, and my initial thought was to use a power supply and changeover relay. After a bit of digging in the OEM manuals, I've found the wiring diagrams and I am now completely stumped! I've had about 10 ideas of different ways to wire the circuit, and the more I seem to try and figure it out the further away from a solution I seem to get. What I want to try and achieve, using a DPDT switch if possible:

Pos 1) low speed

Neutral) parked

Pos 2) high speed

What I can see is, the motor gets power on pin 4 and then to run the motor at low speed pin 2 gets grounded, on high speed pin 1 gets grounded and to park the wipers pin 5 is grounded and then the ground is removed by the integrated control unit.

Can anybody point me in the right direction with this?


Attached Files

I think you would need a SPDT Switch for that, and the integrated control unit.

You connect a chassis ground into the "common" terminal of your switch (usually the middle terminal).

You connect pin 2 of wiper motor to one side of your switch

You connect pin 1 of wiper motor to the other side of the switch

You connect pin 3 of wiper motor to chassis ground.

Wire the integrated control unit as per wiring diagram (no need for intermittent input), and it should park get parked when your switch will be in the OFF position. Just remember that the image shown in your second picture don't show all the wires coming into the integrated control unit.

Hi Frank, thanks for the reply. I should have mentioned that I'm trying to accomplish this without the use of the ICM, as I'm re wiring the car using a Bussmann RTMR. While the ICM is removable from the fusebox, it is quite a cumbersome unit and I'd prefer to try and do this using a combination of relays if possible, as I think it will a much neater solution.

If anyone has any ideas or recommendations, let me know as I'm going to try and bench test this soon.

Depending on the signal that the cam switch operate in the wiper motor, you could use a relay that keep the motor grounded on low speed to park it. That could be done by running a wire in parallel from the low speed circuit of your SPDT switch, to the terminal 30 of the relay, then you ground terminal 87 or 87a (depending if the cam switch apply or remove ground or power to tell if the wiper motor is in the park position), and use terminal 86 and 85 to control your relay from the signal of the cam switch.

So when you put your wiper switch in the OFF position, the additional (parallel) wire would keep the wiper motor running on low speed until the cam switch command the relay to switch state, then no more ground will be applied to the wiper motor, and it will stop running.

Yes I think I'm following you. So If I wire it like below it should work, providing the cam switch sends out power from pin 5 to park the wipers, and If it's a ground that's used to park, I'll ground pin 87a on the relay instead.

Attached Files

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