Starter Motor - Ground Circuit
WARNING: This page is about a different car, the 2009 Mercury Milan, 2009 Lincoln MKZ, and 2009 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
A slow cranking condition can be caused by resistance in the ground or return portion of the cranking circuit. Check the voltage drop in the ground circuit as follows:
- Connect the Fluke 77-IV Digital Multimeter positive lead to the starter motor housing (the connection must be clean and free of rust or grease). Connect the negative lead to the negative (-) battery terminal.
- Engage the remote starter switch and crank the engine. Read and record the voltage reading. The reading should be 0.5 volt or less.
- If the voltage is more than 0.5 volt, clean the negative cable connections at the battery, the body ground connections and the starter ground connections. Retest.
- If the voltage is more than 0.5 volt, install a new cable. If the voltage reading is less than 0.5 volt and the engine still cranks slowly, install a new starter motor.