Join Date: Nov 2002
Location: Ontario & Oceanside CA.
Assuming this is a first gen Camaro, I would first make sure the belt/s are not loose and the alternator pulley is not loose. When you put a load on the charging system (turning the lights on)can cause enough slippage to cause the battery to be undercharged. Then have the battery load tested and the alternator and voltage regulator checked. If all are ok, my next guess would be the light switch. The rheostat for the dome light may be the problem. Park the car after using the lights as you would to simulate the no start problem and do a parasitic draw test (easier than it sounds) Disconnect the positive battery cable and put an amp meter between the positive battery terminal and the positive battery cable. (DO NOT ATTEMPT TO START THE CAR) unless of course you want to watch your amp gauge blow up! You can then play with the light switch to see the draw on the gauge. Opening the doors and turning on other things will cause the gauge to move to the negative side of zero. With all power off, the gauge should read zero. If it doesn't, check everything electrical by pulling one fuse at a time until you get a zero reading. Things that are not fused by regular fuses, like lights will have to be unplugged to check for a draw on the battery. If you see that unplugging the light switch with the lights and dome light OFF allows the gauge to read zero, then you have found the problem. I'll admit, this is a little confusing, but if you understand this, you can handle most electrical problems in the early cars. One thing to note, 99 percent of the electrical problems I fix are from bad grounds.
Hope this helps.