Both headlites are dim brites are fine - 2002 Chevrolet Cavalier Coupe

both headlights just dim no brights Google Search
Could possibly be dimmer switch relay switch?

First I would suspect the dimmer switch on the steering column or wiring in the column. Second I would suspect a bad ground wire or ground connection. Here is link to a forum where others are having lighting problems with daylight running lights. The whole DRL system is rather a complicated maze of relays and connections, any of which could cause your problem. The tip on the forum to get a wiring diagram form Autozone looks like a good deal.

Headlight Wiring Diagram 02 F250 DRL Ford Truck Enthusiasts Forums

dual filament bulbs, check low filament in lamp, they sometimes blow and high filament still burns. sounds like a $6.99 fix

There is a set of wires that go to the bulb for both dim and bright. So the most likly cause is a bad connection at the bulb itself, check for corrosion.

This sounds like a bad battery, take the car to your local auto parts store. Have them check the battery. If there is some other problem they can trouble shoot the charging / starting system also.

Use a volt meter or a test lite ,check for power at the bulb or on the wire to the bulb also check the ground wire to see if it supplys a ground circuit.Look for wires loose from the headlites ground circuit.If equiped it will be close by,A black wire with a screw to framework for a ground.If you have 4 hd lites make sure you dim and or brighten the lites while you look for problem. There may be a fuse for each side of the headlites right and left!

hi!!

Check wiring, specially the plug on dimmer control, look for loose connector and ground, if OK, check dimmer switch resistance (brite = less oms, dim = more oms.) if no or uneven reading, replace dimmer switch.

Good luck,

i think it mite be ur alternator. killing ur battery. chek if ur lites r brite. if they r dim it is the alternator.

If your lights are dimming when the brakes are applied you have one of two problems. First cgheck all of your lights to make sure they all work properly. In other words none are out or dim. If all are fixed or working without problems check the grounds for the brake and headlights. The problem occurs when grounds become loose, dirty, or are starting to break.

Check your headlight black groud wires & clean connections. Also daytime running light module could be defective.