When I turn on my head lights, after about 20 minutes they start to flicker. I replaced both my hi-low beam switch and the actual head light switch. I ideas to fix this problem...Im stumped.

 

Sounds like a bad ground connection or wire. The headlight wiring is getting hot, the ground resistance is going up causing the lights to flicker.

 

it could be a ground or posibly the alt. when it warms up the output is droping off and the light get brighter when the engine speed is higher.

 

ok im having the same problem, i justput some h4 head lights on, the ones the smoked color ones on ebay, and when i turn my head lights on, about 10 sec later all head lights star to flicker...any help help that

 

Check your grounds and charging system voltage should be around 13.8-14.0. If the lamps only flicker check the grounds at the front near the head lamps you might have one that is loose.

 

I figured out my problem with the flickering and it sound like you may have the some one. I installed fog lights on my car and just tapped into the power source of the head lights. When I turned my head lights on, the fog lights would come on too. What was happening was the head lights and fog lights together were drawing too much current and the wires were getting hot and shorting out causing all the lights to flicker. To solve the problem I just put the fog lights on their own power source and fuse and added a seperate switch for them also. They have been working fine ever since. If you installed you h4 lights the same way, you probably have the same problem. Let me know how you make out.