Low beam headlights not coming on.

What make model an year vehicl ?

It shouldn't be the high/low beam switch, as that switches the high/low beam relays. One high beam relay supplies power for both sides, one for low beam, both sides. If you were to lose switch function or a relay, you would lose the high beams or the low beams, but not for just one side. It would be interesting to probe the fuses with a test light and see if you're getting power to and through them. If you are, the problem would be between the fuse box and the headlight, if your not getting power to the left head light fuses, the problem will be in the fuse box. Good luck!

You need a wiring chart to find the color code . however there are three wires , earth, low beam , high beam, to find same turn lights to high beam, with a vault meter neg. probe to earth probe each wire the live wire is high beam , dip lights and probe again live wire is low beam , other wire is earth wire.

These trucks are known for bad multifuction switches.
the switch that i talk of is the signal switch , the handle is the switch, it bolts to side of steering column . this switch controls the signals and the headlights and high /low beams. the other thing is the headlight switch connector, the connector some times goes bad and starts to melt or just comes out of the connector. you will need to remove the cover to steering column, the screws are located under the bottom cover in holes. remove cover and check connector and then test for power if you have power going into switch but not coming out then switch is bad.

the last thing is to make sure the bulbs are good , make sure the headlight bulbs are good , and also the driving light bulbs, test for power at the connectors to those lights to.
You will need to do a little testing to find the problem.

if replacing the high beam bulbs do not fix the DRL issue ,see my tip under 2001 to 2005 civic daytime module repair.The accord you have has the same module.

Did you check the relays? or the High beam switch? Usually you can trace the wiring down from the switch to a harness at bottom of steering column use test light there too.Use a Test Light at the headlight connection make sure that you have power Low beam then test high beam. If you can't figure out use of Test light, it has a ground clip and a probe (Sharp end)Ground the clip on something metal (on car) use the probe to touch wire (one at a time) in the socket where the headlight connections. 1 wire is ground 1 is LOW beam and other is HIGH beam. may need a mechanic to check the switch. The light on the tester will light up IF you have 12 volts. NO LIGHT NO POWER!

Hi, the problem can be the relay or the body control module. The thing to do is pull the low beam relay out of the relay box under the hood and swap it wil the high beam relay. If the low beams start working instead of the low beams, buy another relay for the high beams. If there is no change, pull the relay out again and interrogate the relay socket with a 12 volt test light or voltmeter. Connect your test light clip to chassis ground and probe the relay socket. There should be 2 hot terminals in the socket. If not, there is a problem with the fuse box. If you get these 2 hot terminals, move your test light clip to battery positive and probe the other 2 terminals in the socket. With the headlight switch off, there should be one terminal that lights the test light dimly. If not, there is a problem with the wire from the relay to the headlights. If this is OK, next turn the headlights on (low beam setting) and probe the socket again. There should now be 2 terminals that light the test light. If not, there is a problem with the wiring from the body control module, the module itself, or the beam control switch. If you get to this point, you will need to check the signals AT the BCM to determine if the BCM is to blame of the switch. Please get back to me for these additional steps, if you get stuck here.

should be three wires one ground one power for low beam one power for high beams

unplug connector
take a test light (if dont own one buy one there real cheap and useful) clamp test light to good ground turn on lights on low beam probe wires in connector until test light lights this will be low beam power
no switch to high beams should have power on other wire

Power for the headlights on the Left side (High and low beam.) comes from the same fuse... The ORANGE wire and the ORANGE/BLACK are the same, they connect in the harness. If you only lack the 12v to make the light work connect them at the headlight assembly.

If your low beam also lacks ground the Left low beam ground is shared with the right low beam ground... Run a wire from left low beam DARK BLUE to right low beam DARK BLUE/WHITE.

If its not working now then your cursed, seek a witch doctor.

Take a look at this link regarding DRL system. I know it's not exact truck but most of it would apply to yours too. It should give you hints on what to test & how.
http://www.fordf150.net/howto/drl.php