Headlight will not come on, high beams will not come on , the passing lights work, brake lights work. and then randomly the headlight will start to work

Usea test light and follow the fuse to the lamp fitting.

the switch supplies power to the relays that switch on the lights according to the position you have it at
so on high beam there will be 2 high beam lights working
on low beam there will be 2 low beam lights working
back to passing lights or flashing head lights , both beams will work so the switch is the last item to consider
Now with only one side beam not working it comes back to the ground on that light for that bulb
remember that electricity follows the path of least resistance so it the ground is bad the current will ground out through another point including a light which will switch that light off or make it not work
remember the brakes light that flask when an indicator is used --same thing

main power issues .. check battery connections.. check fuseable link wires under hood,..check fuses in fusebox for blown fuses and check wiring harnes ground connections especially by the headlights..

There are few solved help links,related to these types of issue.Click the link below and go through its procedure:------2004 Dodge Ram: High Beam Light is DIM? http://technoanswers.blogspot.in/2012/04/2004-dodge-ram-high-beam-light-is-dim.html
----------High beams stopped working but headlights still work? http://howtobyme.blogspot.com/2011/11/highbeams-stopped-working-but.html
----------• Working of Headlight switch? ---------

• Both headlight bulbs blow together? -------------

• Car headlight bulbs don't last long?
---------These details will helpThanks.

it s the headlight switch or headlight module

more than likely a fuse or a relay is bad. locate the fuse for the headlights (owners manual) and check if it is bad, if the fuse is good, find the relay and give it a flick or two and try the headlights then, if they work, its time for a new relay

There is a relay that controls the headlights, volvo calls it a step relay. You will have to check that power is getting to this relay. If not, check all fuses and wiring. If power supply checks out ok, you may have to replace the relay. Let me know if you need any more info or a wiring diagram.

Hi the first thing I check on for anyelectrical problem is a bad ground connection. Follow the headlight wires as far as you can, even when they disappear into a larger covered loom at random places, maybe even right next to each light, you will find a wire or several attached to ground, could be a inner fender, engine, etc.. sometimes a inner fender ground is just a selftapping screw, It may be rusted out or just loose. Headlights work through relays that are also located in the fuse boxes. I assume you have checked both fuse boxes, in the truck and under the hood, good luck, Chuck

possibly head lamp switch. daytime running lights on separate circuit and use the high beams at reduced voltage. does flash to pass work? that's high beams too. do high beams work?

Is it just low beams?
do taillights work?

Ckeck the headlight connections they are notorious for corroding. Check the ground connection for the lights. Pull your dimmer switch back as if you were flashing a car to pass and see if they work there. If they do you have a dimmer switch problem.