A relay typically has two sets of connections. One set is a wound wire coil that makes the magnetic field that pull in the contacts. The otehr set of connections are the relay's contacts which provide the path for current to flow through the load. So it depends on what you are measuring as to whether 6 ohms is continuity or not. In a relay coil, you expect to see some small current flow (12V/6 ohms = 2 amps), so that would be reasonable and constitute continuity. However, it this is the contacts you are measuring, then with the 20A starter solenoid load, you can see there is no way for a 6 ohm resistance to support a 20A current flow in a 12 volt system (bottom line the starter solenoid likely will not pull in).