Turn Signal Bulb - Rear

This procedure covers the replacement of rear turn signal bulbs on a 2007 Ram 3500, accessed from inside the truck bed.

Warnings

Tools required

Parts

• Rear turn signal bulb × 1 — 3157 or 3157A amber bulb

Preparation

1. Park vehicle on level surface and turn off ignition
2. Lower tailgate for easier access to tail light assemblies
3. Identify which side requires bulb replacement by checking turn signal operation

Procedure

1. 1

   Access tail light assembly from truck bed
   From the rear of the truck, locate the two exposed fasteners (Phillips or Torx) on the outboard edge of the tail light assembly. Remove these fasteners to release the tail light housing from the bedside.
2. 2

   Remove access panel
   After removing the two outboard fasteners, grasp the tail light assembly and pull it straight back (rearward) to disengage the locating pins/retainers. Ease the assembly out to expose the bulb sockets on the back side.
3. 3

   Locate turn signal bulb socket
   With the tail light assembly pulled out, identify the turn signal bulb socket on the rear face of the housing. On this truck the turn/stop function typically uses a 3157 bulb; identify the correct socket by its position in the assembly.
4. 4

   Remove bulb socket from housing
   Grasp the bulb socket firmly and rotate it counterclockwise approximately 1/4 turn until it releases from the tail light housing. Pull the socket straight out to remove it from the assembly.
5. 5

   Remove failed bulb
   With the socket removed, push the bulb into the socket slightly and rotate counterclockwise to release it from the socket. Pull the bulb straight out. Inspect the socket for any corrosion or damage to the contacts.
6. 6

   Install new bulb
   Insert the new 3157 amber turn signal bulb into the socket. Push in slightly and rotate clockwise until it locks into place. Ensure the bulb is fully seated and secure in the socket.
7. 7

   Reinstall socket into housing
   Insert the bulb socket back into the tail light housing, aligning the tabs properly. Push in and rotate clockwise approximately 1/4 turn until the socket locks securely into the housing.
8. 8

   Reinstall access panel
   Reseat the tail light assembly onto its locating pins/retainers and push it forward until seated. Reinstall the two outboard fasteners and tighten until snug; do not overtighten.

Reassembly

1. Ensure access panel is fully secured to prevent water intrusion into the bed area
2. Close tailgate and ensure it latches properly

Verification

• Turn ignition to the ON position without starting the engine
• Activate the turn signal on the side where the bulb was replaced and verify it flashes at normal speed
• Walk around the vehicle to visually confirm the new turn signal bulb is illuminating properly
• Check that the turn signal indicator on the instrument cluster is flashing at normal speed, not rapidly (which would indicate a bulb still out)
• Test hazard lights to confirm both rear turn signals function correctly

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle