My 2006 Ford F150 would not start and the lights flashed in the dash when I tried to start it. I removed the starter which is only 4 months old, it bench tested as perfect. I removed the battery which is only 10 months old and took it to a shop to be tested. All cells are 100% and it holds a charge fine.
I tried to run a new ground wire from the battery to the starter. No change! I checked the continuity of the ground wire in the car and I got 0.5 to 0.9 fluctuating.
Next I wanted to test the voltage drop when the starter clicking. But I forgot to reconnect the ground wire and it started. It started without any ground to the starter. It is running and I took it for a drive with the ground wire detached.
Would could the problem be? Something else is grounding the motor?