I went out to start my car this morning ,91 lx auto, and nothing happened, no crank and seemed to have low battery power so I hooked up the charger thinking I must have left a light on or something to drain the battery. I decided to check the battery and had 12.5 volts. Went to try and start it again and no power so I hooked up the charger and tried to start it again this time the Main Relay was clicking very rapidly and the interior lights would dim for a few seconds then it would stop and the lights would get brighter. When I took the charger back off there was not enough power for anything. The headlights were dim too. I checked the head light fuses in the under hood box and there was 2 volts to both fuses.

I unplugged the injector wiring plug and tried starting with the charger back on the battery and the relay did not click rapidly, plugged it back in and it clicked rapidly again. I also changed the main relay with a spare same results.

I'm Stumped.

 

Either bad battery or very corroded battery connections not allowing adequate power for operation.

good luck

 

I had the charger hooked up to it and the battery was reading 12+ volts. I'll swap batteries and see if there is a difference.

 

Battery voltage by itself is not a good indicator of battery charge or ability to generate cranking amps. It also will not tell you if battery connections are good.

Try measuing battery voltage while cranking. If it drops low (< 11 volts perhaps), the battery is not going to start the car.

Check the battery connections first.

good luck

 

put a voltmeter on the battery, 12.5 volts static, the battery is good, put a load on it (no battery tester, turn headlights on and run fan on high) watch the drop, should drop to 9 or 10 volts, run and shut off the draws and run back to voltmeter, should spring back into the 12 volt neighborhood.
if battery checks out, replace the starter.