Distributor Pick-Up Coil Short And Resistance Checks

1. Disconnect pick-up coil leads from HEI-EST module terminals "N" and "P" (usually a Green and a White wire). To check for shorted pick-up coil, set ohmmeter in middle range.
2. Connect one lead to either pick-up coil lead and other lead to distributor housing. Flex pick-up coil leads by hand to check for intermittent shorts. See Fig 1 and Fig 2. Reading should be infinite at all times. If not, replace pick-up coil.
   Fig 1: Distributor Pick-Up Coil Short & Resistance Checks Integral mounted ignition coil.

   
3. Connect ohmmeter leads to both pick-up coil leads. See Fig 1 and Fig 2. Flex wires and connectors to locate intermittent opens. Resistance should read a constant unchanging value between 500 and 1500 ohms. If not, replace pick-up coil.

Fig 2: Distributor Pick-Up Coil Short & Resistance Checks Externally mounted ignition coil.