Here is my problem I have an 89 cavalier the engine runs great until I turn the lights on or put it in gear or step on the break the car dies like I had a kill switch on it but it does not have an alarm installed. I think a wire is grounding out on something I changed the head gasket recently and the computer a few months ago I got a haynes manual but I just don't know where to start for this problem it just started this today... any ideas

1. Check all under-hood and under-dash fuses with a test light or multimeter. Read section X below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-honda-civics-46563.html

2. Check for DTCs.
3. Check ignition switch and harness.
4. Check alternator and alternator wiring.
5. Clean main ECM ground and main engine ground.
6. Review wiring for obvious abnormalities.

Sound like the alternator may not be charging properly, to me.