A couple months ago my '89 Thunderbird wouldn't start. So it was towed to the dealership and was "fixed" by replacing the starter. I was told that everything else was fine.
Two weeks later the car won't start...replaced the firewall mounted celinoid and put in a fresh battery.
Two weeks later car won't start...replaced battery cables from the starter to the celinoid AND the celinoid to the battery (2 wires).
TODAY the car would not start...tightened the battery cables and drove to the autoparts store and did another electrical systems check. The test read that everything is fine, but the battery performance was terrible. So I took the battery out and had them run a diagnostic on IT. Turns out that the battery is fine...with over 525 cranking amps and 13 volts
MY POINT: I think that there is still something in the cars' electrical loop that is stealing away electricity...maybe the ignition or some wire that is grounding out (?) your comments are welcome. Thanks.