MoTec PDM30 and Alternator wiring

Hey guys,

Wondering if the setup in the attached diagram will work to use my Motec PDM30 to wake up my Astra power steering pump based on alternator output (engine run status).

Essentially the alternator charge light will be wired as normal with the wire coming from the alternator spliced to an input on the PDM that can be used to trigger a the output for the pump.

Hello Adam,

Are you trying to kill the activation of the pump if the alternator goes bad ? Without a charging failure, the input will stay high and if the light turns ON, the input will be pulled down allowing you to use some kind of logic to turn off the output for the pump.

Hey Chuck,

Thanks for the reply, I ended up speaking to MoTec as well who advised what I wanted to do with the input idea wouldn't work properly so I've just wired the charge light as normal for now, until I upgrade to an ECU with a CAN output so I can program the pump to wake up based on engine speed.

You should be able to enable an output on your PDM to send a wake up signal after it sees an RPM of say 600rpm. That way when cranking it keeps the PS pump off and as soon as the engine hits an RPM above cranking (engine running) then it turns out the PS pump output.