Jerry, The RPM relay is turned on by the pulses from the pulse coil in the distributor. The coil should read about 600 ohms cold and can go to 700 ohms hot. It turns on the RPM when the engine starts to turn over. John Hervey www.specialTauto.com I have lots of info on the web site about them. << Can anyone tell me what picks the RPM relay? I understand what keeps it picked, I just cannot find what picks it. The reason I ask is mine will not pick, but if I help it to pick it will stay picked and the car runs fine. Oh I know, buy a new one and don't worry about it, unless the new one needs help to. Most places will not take back electronic parts. I would just like to know where the pick comes from so I could check and clean, etc. Thanks Jerry V >>