I recently bought a 1998 chevy S10 4x4 pickup, the daylight running lights were on...so I thought all lights were OK....wrong, I turn the switch to headlights at night...no lights, the DRL will light up in the day but I can't get any headlights at night....and the dimmer switch doesn't even bring the DRL on bright. I replaced the headlight switch and all the fuses are OK.....what's next?

SOURCE: DRL-1998 Cavalier Z24

Check your DRL relay that is located in the fuse box. Also check the connector under the battery box for corrosion. (Not a smart place to put a connector) GM really messed up with the wiring on the 98-00 cavaliers headlights.

SOURCE: CHEVY 1500 TRUCK HEADLIGHTS TURN OFF WHEN YOU TURN ON SWITCH

If you have replaced the switch, and it is still doing it it sounds like you definately have a short somewhere in your wiring. On the other hand if the dimmer is in the turn signal arm ( forward bright back dim ) the problem could also be there in the dimmer switch, such as a short being caused by that dimmer switch being faulty.Auto Zone and Discount Auto Parts both test a lot of your electrical problems for free, and/or may have some knowledge to more accurately pin point the problem. Not sure about Pep Boys or some of the other discount auto part chains.