Jim Grant's Tech Tips
'00 Chevy Cavalier Z-24, No Headlights
Q: When I start my '00 Chevy Cavalier Z-24 and put it in drive, the daytime headlights come on. However, when I turn on the headlights there is nothing, low or high beam. Only when I hold the lever back will the lights come on, but when released the lights go back out. Relay or switch or ???? How do I find out?
- Bob W.
A: I'm inclined to believe you have a headlight switch problem and here's why. There are 2 fuses one for each of the headlights on the vehicle. For the daytime running lights (DRL) to operate the fuse and wiring to the right head light has to be good, because it supplies the power for both headlights in the DRL mode. The fuse and wiring for the left headlight has to be good because the DRL relay needs power from that fuse to operate. The DRL relay in turn provides a path through the left headlight and wiring to ground. When you pull back on the dimmer switch, you are activating the flash to pass circuit of the headlight switch assembly. Because the flash to pass mode works you then know that the high beam wiring and headlight bulbs are in good condition. This also tells you that the ground circuit for the headlight switch is good. In many newer vehicles, the headlight switch doesn't provide power to the lights. The headlight switch has now become the path to ground to complete the circuit. The headlight switch and the high/low beam dimmer control are one assembly so when you replace one you get the other free. Such a deal! My coffee bet is on the headlight switch assembly.