MoTeC Global Forum

I would like to ask you all for some guidance and to see if anyone has successfully setup a RainGear wiper motor with their PDM. Attached are the wiring instructions from RainGear.

My wiper motor operates with a single 12V input and the low and high speed inputs appear to switch to ground when selected. After looking through all the posts on this topic, I see others have had similar wiper motor wiring but not sure if they were able to setup the PDM to control the wiper motor as planned.

I would like to use the PDM and CAN/keypad to control the wipers as indicated in several of the PDM example wiper config files. Since the PDM outputs switch to 12V and if I were to run the High Speed and Low Speed wires from separate PDM outputs, the motor would then be running in reverse, correct? How would the Park switch then work with the PDM?

Thanks,
Neil

If you need to switch to ground one option is to use a relay. So you can convert the signal from the pdm. Bit of a waste of pdm channels though.

greenamex2, exactly, and that is what I am hoping to avoid.

I will do a wiper motor bench test using the switch/controller provided with the kit and then will try provide power only to the Low or High speed wires and will note the direction of the motor and will see if I can get the Park feature to function (to simulate the PDM as the controller). In the meantime, I will proceed with building the PDM harness as I am looking to get this car running....the wipers can wait

I'll report back with what I learn.

I would advise against powering the wiper motor backwards.

Common positive wiper motors aren't unusual. You can still set this up to work with the PDM the only exception being you use a relay to switch from the high speed to the low speed winding.

I have attached an example circuit.

Thank you, SOReilly, for your response and the detailed diagram, nice. I very much appreciate your input!

Couple questions..... in your diagram, Output 9 is the LOW speed channel and Output 29 is the HIGH speed channel I presume, and each of these PDM Output channels would be connected directly to the 5-pole relay which would switch the motor to ground when activated (also, I believe this configuration would only function as intended with the +12V supply to the single supply wire on the wiper motor harness).

Regarding the Park switch. The single +12V ign feed to the motor harness should provide constant power to the park switch, and when the wipers are shut off, the park switch wire (blue) will be grounded and the wipers will return to their parked position. If this is correct, is an additional relay required for the Park wire and another PDM output would be activated or 'true' when the wipers are not in any of the intermittent, low, or high speed modes?

Thanks!

Hi,

Correct, Output 9 should always be used for the Low Speed winding for the wiper (or if ONLY the high speed winding is wired to the PDM) and the High speed is linked in the setup for Output 9*. What is happening in the diagram is that Output 9 is providing the power for both motors, but only one is grounded at any time by the relay. When Output 29 is powered, this switches the relay from the NC pin that is grounding the Low Speed Wiper motor, to the NO pin that then grounds the High Speed Wiper Motor and turns it on.

(*) In your setup, as Output 9 needs to remain active for the whole operation, you would keep this unlinked and use Output 29 as a standalone switched output as Output 29 does not directly drive the motor, it only switches the relay on or off.

The Park switch should be wired directly to one of the inputs on the PDM and used as part of the logic to control the operation of the wipers. The Set:Reset function in the PDM can use the Park Switch input as the reset function, this keeps the output live until the State of the Park Switch changes to indicate that it is in Park, and then resets the output.

Thank you, Stephen! This is very helpful.