high beam headlamps don't come on, 85 celica,low beams do work

In this model,it will be both high beam bulbs,are bad or it will be the dimmer switch.

Have you checked the fuses yet? To test the wiring and or bulbs you'll need a test light and an ohm meter. Remove the connector from the headlight and connect the light in place of the bulb ( one end of the test light should be connected to one of wires going into the headlamp ( + ) the other end of the test light should be connected to the other wire going to the headlamp ( - ) ) there should be 3 wires to each headlamp one power wire will be for low beam and another power wire will be for high beam the headlamp share a common ground. After you connect the test light turn on your headlights on if the test light turns on you are connected to the low beam or you have the high beams on. operate your high beams to see if the test light turns on. if it does your headlamp is bad just replace it . If it does not light swap your test light leads and try it again if you still do not get anything you have a wiring issue a relay or switch problem. which will take more time to explain. To confirm a bad headlamp you can also test the bulb with an ohm meter a good filament will have continuity from the power connections to ground you test this on the bulb at the three spade connectors. hope this helps.