Low beam not working, LAMPF on display. Had a bad battery when I noticed this problem. One bad cell. Replaced battery, problem remains. I have installed HID's, but there is simply no voltage to the low beam socket, at all. No voltage at the headlight fuse under the beak either. I also have a SERVICE indication on the display. What can I do to clear the SERVICE indication, and how do I get my low beam to light up again.

Headlamps
You can use the headlamps two different ways.
• Place the headlamp switch in the HEAD position for normal operations
• Place the headlamp switch in the OFF position for automatic lamp control (ALC) operation. During ALC the low beam headlamps are ON for daytime running lamp (DRL) operation in daylight conditions at reduced intensity or low beam headlamps ON at full intensity with exterior park lamps ON in low light conditions.
The body control module (BCM) applies a pulse width modulated (PWM) voltage to the headlamp module and high beam relay in the underhood fuse block. The ground for the headlamp module is supplied from G113 or G115. For normal manual low beam operation when the headlamp switch is place in the HEAD position, ground from G202 is applied through the headlamp switch and to the BCM through the headlamp switch headlamps ON signal circuit. The BCM then applies a PWM voltage to the headlamp module/high beam relay voltage supply circuit. The headlamp module then applies battery positive voltage through the left front (LF) and right front (RF) LO Beam fuses to the left and right low beam headlamps. The ground for the left headlamps is supplied by G101 and the ground for the right headlamp is supplied by G100.
For high beam operation, ground is applied at all times to the headlamp dimmer switch from G202. When the headlamp dimmer switch is placed in the HIGH position, ground is then applied through the headlamp dimmer switch signal circuit to the BCM. The BCM then applies a ground to the headlamp high beam relay control circuit. This energizes the HI Beam relay, the relay then applies battery positive voltage through the LF and RF HI BEAM fuses to the LF and RF high beam headlamps. The ground for the left headlamps is supplied by G101 and the ground for the right headlamp is supplied by G100.
The BCM then sends a class 2 message to the instrument cluster in order to illuminate the high beam indicator lamp. If the headlamp switch is left in the HEAD position, the inadvertent power control feature will turn OFF the headlamps after 10 minutes after you turn the ignition switch to the OFF position. If you place the headlamp switch in the head position after the ignition switch has been turned OFF, or if the ignition switch is in ACCY position, the headlamps will remain ON until you turn them OFF or until the battery runs dead.

Replace bulb with side that is workinh high and low beam if that dont work has to be a wiring problem

First check light relay fuse, if ok check battery voltage at low beam light terminal, if ok replace low beam bulb, if no voltage check switch side of relay, if voltage replace relay, if no voltage check headlight low beam switch.

Check your connections at the wiring harness going to headlights for corrosion, sounds like high resistance somewhere, also make sure your ground wires are secure. It wouldn't be the alternator or the battery would be dead and not start the engine. Also shouldn't be any condensation in your head light assembly's or will cause bulbs to blow prematurely.

ok if you run a power wire to the positive on battery does it go?
if so its a plug or cable issue. if not make an earth wire for the earth side of light and try the power again. if it goes you have a bad earth.

I would start with checking the headlight bulbs (slim to none possibility but starting point) next go to the headlight switch.

If your headlight switch is the type you pull out, left of the sterr column on dash, switches tend to go bad, I replaced mine and only had 50,000 miles. try checking headlight relay in engine fuse box first.
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This sounds like a loose connection/bad wire somewhere for the low beam lights. Can't really give you more information without seeing the vehicle, and wiring diagram for the circuit. Usually, things that go on and off when hitting bumps are connection/wiring problems. The fact that one of your low beam headlamps burnt supports this theory. Bad connections or wiring mean lower voltage, thus higher amperage at the bulb, motor or whatever it's running, which makes them burn a lot quicker.

Check your hi/low beam switch. It sounds like you are not getting power through the switch on low beams.