What would cause my brake lights, tail lights and my rear turn signals to stop working on my 1998 Ford F150 XL pick up truck. Also my ABS light came on and my gas guage went from 1/4 tank to Full tank

Abs detects each wheel of the rotation.i will check from the tire then monitor with the scanner to see the abs sensor on each wheel and chk any fault code as well.anyone of the abs sensor have not detect correctly,it will be not working right.that's the basic of ABS.good luck

check the fuse foe the stop lights-Denny

Have you checked the socket to see if 12 volts is reaching the socket for brake light citcuit? Probe the wires with a 12 volt test light probe (avail from any parts store for about $6)

Hope this helps your out. I know the diagram and locator is a bit blurry but hopefully it gets what you need.
Drivers kick panel:
Front wiper 20A - Front wiper system Cigar 15A- Cigarette lighter Audio 10A- Audio, remote control mirror Air Bag 10A -Air bag diagnostics Stop lights- 15A -Rear brake light, high mounted stop light ECU B+ 10A - Shift lock actuator, transaxle controle module, radio, engine control module Room 10A - Interior light, clock, ignition key reminder, rear cargo area light switch ABS 10A- Anti lock brake system control unit ECU IG1 10A - Transaxle control module, shift lock actuator, ABS control unit, DRL unit Meter 10A - Instrument panel, back-up switch, electronics time control module, inhibit switch Turn signal 10A- Hazard switch ,front and rear turn lights, turn indicator IGN1 20A - Ignition switch ABS 30A- ABS pump motor TNS 30A- Tail light, license plate light COOL/FAN 30A- Cooling fan Cond/Fan 20A- A/C condenser fan Starter 15A- Start signal , Fuel pump Blower 25A- Blower Motor SR/ACC 10A - Ignition switch Hazard 15A - Hazard and turn signal light D/Lock 25A- Door locks ABS 30A - Anti lock brake system control P/W RH 20A- Power window motor right hand P/W LH 20A- Power window motor left hand IGN2 25A- Ignition Switch
Engine compartment :
Head 25A- headlights IG 2 30A- Ignition switch IG coil 15A -Ignition coil, condenser,generator IC regulator, diagnostic connector. O2 down 10A- Rear O2 sensor O2 up 10A- Front O2 sensor Fuel pump 10A -Fuel pump unit Injector 10A -Fuel injector ,camshaft positioning sensor, purge solenoid valve, EVAP, IAC actuator, Mass Airflow sensor, EGR stepper motor. fuel pump relay coil, vehicle speed sensor. A/Con 10A - A/C compressor controls, cooling fan BTN 30A- Brake light , high mounted stop light. Tail light LH 10A- License plate light, tail light , rear combo light, instrument panel illumination Tail light RH 10A-License plate light, tail light , rear combo light, instrument panel illumination Head low 15A- Headlight Head Hi 15A-Headlight Horn 15A- Horn

Inside kick panel

bad ground on tail lights

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under the hood, there may be fuses for the trailer lights.

SOUND LIKE TURN SIGNAL SWITCH COULD BE BAD.SOME CARS BRAKE LIGHT CIRCUIT SHARES THE REAR PORTION OF THE TURN SIGNAL CIRCUIT.

probab;y a faulty ground problem.

check fuse number 7 in Engine Compartment Fuse Box , if its ok you need change turn signal switch

The signal lights work through a relay but the brake lights work through the signal switch, if both are out I think you'll find the problem is the signal switch.