Only when you turn on the headlights,the left blinker goes real fast and the dash lights go dimmer

I wopuld suggest you replace the dimmer control switch for the dash lighting.

i don't have a real good answer, soooo just remove the dome light bulb so you can drive it

you dont know where the dimmer is? on the left, on the headlamp switch or a small knob.

Bad ground, or check all your bulbs. Usually its a ground in the back of the truck under where the spare is. If its not the ground check the bulbs. Please rate Thank you

you have a short in the wireing fix it fast before you have a "fire"

I would start by checking the blinker light bulb on the left side front and or rear,some vehicles will blink real fast and some wont blink at all when a bulb goes bad.

Usually a fast turn signal means that there is a light out. You should probably check all of your lights, including back-up lights, and turn signals. If there is one out then replacing the burnt out bulb should fix the problem.

The blinker usually blinks fast when a turn signal light is burnt or not contacting. Check the signal bulbs to see if they are contacting or in good condition. If that is not it. Try replacing the blinker under the dash.

you have you interior light dimmer turned way down. when the lights are off all your digital dash has full lights. when the lights get turned on it goes off the dimmer. it should be by the left of the steering wheel on the dash. just turn it up and the lights will be as bright as you want even after the car head lights turn on.

sound like the problem is in the turn signal switch