I have a 1990 chevy 1500 and i lost headlights and dash lights and radio and ciggerette lighter all fuses appear good under dash is there a relay or something else i should look for?

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.

SOURCE: turn signal relay switch, 94 s10 chevy blazer

The Turn signal relay on a 94 s10 blazer is located under the cluster area right behind the panel that holds the parking brake release handle you will see it once a couple of trim panels get remove it will be to the right side of the brake release handle

SOURCE: 2001 chevy silverado 1500 headlights wont shut off

You will have to have the dealer reset the security light to restart vehicle.Check all engine and chassie grounds because this is where the lighting would exit the vehicle.It sounds like a ground burnt through.

SOURCE: 99 chevy 1500 with DRL feature; headlights won't

change the headlight switch!! itself its broken inside the unner contacts

SOURCE: Both headlights went out on 98 Chevy S10. Fuses

Could be the headlights themselves. test them using a power source