i have an '02 civic lx. while driving, the headlights dim as i drive. they don't dim all the time, but i notice that when electrical components are turned on they do. for example, the defroster, brake lights, rolling up/ down windows. when im driving and the engine revs more than 2500 rpm, they get brighter. i had the alternator tested at my nearest AutoZone, man they're great, and it tested good. i replaced it anyways, and still the same problem. i thought the problem might have been the "cheapy" HID kit, but i took that out and still. any suggestions?

 

welcome to the fourm. Check to besure you have good ground connections for your headlight, also for your chassie gnd. not just look and touch, take off and sand or etch the gnd cable and surface.

 

Just to add to acmech52 you may also want to consider getting adding more grounds especially since it sounds like you are adding demand on to your electrical systems. If you have a big stereo system especially like 1+ amps and other accessories running inside the car you should have a stiffing cap.

 

it is normal to state that consumer will dim the light , what it is not normal is to have it in cycles of 30 seconds.I wrote in the other post that I did some tests at sea level and at high altitude and the system baives totally different.At high sea level 7500 feet the system is crap turning on high speed vents in cycles of 30 seconds.At sea level the system works fine and some times the high speed of the vents turn on for a while like 5 to 10 minutes.It is related to the presure sensor of the A/C system, changing it for a similar one less sensible or probalby more sensible it will change this funny or anoying dimming because of turning high speeds vents.Also it is funny that at a hot day when you start the enigne for the first time of the day and righ away turn on the A/C it will start cooling and the vent cycling will not start until the engine is hot.Another way of improoving the system is a ECU flasing update.If the light dimming is the problem you can buy HID lights and this will also stop dimming.

 

Ill check the batt volt when running. And no there are no lights indicating any probs other than the lights just dimming. The Batt Light does not come on.