This procedure covers removal and replacement of the center high-mounted stop lamp (CHMSL/third brake light) assembly on a 2014 Ram 2500, including electrical connector service and seal inspection.

Warnings

Tools required

Parts

• Third brake light assembly (CHMSL) × 1 — Use OEM specification or verified aftermarket equivalent
• Mounting gasket/seal (if damaged) × 1 — Use OEM specification
• Mounting hardware (if corroded) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn ignition to OFF position and remove key
3. Disconnect negative battery terminal and secure cable away from battery post
4. Wait minimum 2 minutes for electrical system capacitor discharge
5. Locate third brake light assembly - typically mounted at center of rear cargo box rail or cab panel
6. Inspect work area and remove any cargo or tonneau cover that may interfere with access
7. Clean debris and dirt from around the light assembly mounting area to prevent contamination during removal

Procedure

1. 1

   Access third brake light assembly
   From inside the cargo bed or cab rear area, locate the backside of the third brake light assembly. On most 2014 Ram 2500 configurations, access is from inside the cargo bed. Remove any protective covers or bedliner clips that may be blocking access to the mounting hardware. Some configurations may require partial removal of rear cab panel trim.
2. 2

   Document electrical connections
   Before disconnecting anything, visually inspect the electrical connector and wiring harness. Note the connector orientation and routing. If available, use a multimeter to verify voltage at the connector with brake pedal applied (assistant or brake pedal depressor required if battery still connected - skip if already disconnected). Take a photo for reference during reassembly.
3. 3

   Disconnect electrical connector
   Press the connector locking tab and carefully pull the electrical connector straight off the third brake light assembly. Do not pull on wires. Inspect connector terminals for corrosion, damage, or moisture intrusion. Inspect rubber weather seal on connector for cracks or deterioration. Apply dielectric grease to terminals if connector shows signs of moisture exposure.
   ⚠Damaged connector terminals can cause intermittent brake light operation. Replace connector or repair terminals if corrosion or damage is present.
4. 4

   Remove mounting fasteners
   Locate the mounting screws or bolts securing the third brake light assembly to the mounting surface. Typically 2-4 fasteners are used. Using appropriate screwdriver or socket, carefully remove all mounting fasteners. Keep fasteners organized for reinstallation. If fasteners are corroded or stripped, replace with new OEM hardware.
5. 5

   Remove third brake light assembly
   Carefully lift the third brake light assembly away from the mounting surface. The assembly may be sealed with a rubber gasket. Gently work around the perimeter if gasket adhesion is strong. Avoid using excessive force that could crack the lens or housing. Once free, remove assembly completely and set aside on clean surface.
6. 6

   Inspect mounting surface and gasket
   Thoroughly inspect the mounting surface for rust, corrosion, or damage. Clean mounting surface with shop towel to remove dirt, old gasket material, or debris. Inspect the gasket/seal on the removed assembly. If gasket is torn, compressed, or deteriorated, it must be replaced to prevent water intrusion. Check mounting holes for thread damage or elongation.
   ⚠Water intrusion through failed gaskets can cause electrical system damage and premature bulb/LED failure. Always replace deteriorated gaskets.
7. 7

   Prepare new assembly
   Unpack new third brake light assembly and verify it matches the original configuration. Check that the electrical connector type matches. Inspect new gasket is properly seated in assembly groove. If gasket is separate, install it onto the new assembly ensuring it is properly positioned in the gasket channel around the entire perimeter.
8. 8

   Install new third brake light assembly
   Position the new third brake light assembly over the mounting location, carefully aligning mounting holes. Ensure gasket remains properly positioned and does not fold or pinch. Start all mounting fasteners by hand to ensure proper thread engagement and alignment before tightening any fastener. Verify assembly is seated flush against mounting surface.
9. 9

   Torque mounting fasteners
   Using a torque wrench, tighten mounting fasteners in a cross pattern (if multiple fasteners) to the specified torque value. Tighten gradually in stages rather than to full torque in one step to ensure even gasket compression and proper sealing. Final torque depends on fastener type - small screws typically 1.5-3.0 Nm, larger fasteners may require higher values. Reference Cover Screws specification (15.0 Nm / 11.0 lb-ft) if fasteners are 6mm or larger diameter mounting screws.
   Torque spec

   Cover Screws15 Nm (11 lb-ft)
10. 10

    Connect electrical connector
    Route wiring harness to avoid pinch points and sharp edges. Align electrical connector with terminals on new third brake light assembly. Push connector firmly onto assembly until locking tab clicks into place. Gently tug on connector to verify it is fully locked. Verify weather seal on connector is properly seated.
11. 11

    Reconnect battery and test operation
    Reconnect negative battery terminal to battery post. Torque battery terminal bolt to specification (6.0 Nm / 4.0 lb-ft) - do not overtighten as this can damage battery post. Turn ignition to ON position. Have assistant press brake pedal while you verify third brake light illuminates properly. Test multiple times to confirm consistent operation.
    ⚠️VERIFICATION REQUIRED: Do not return vehicle to service without confirming third brake light operates correctly with brake pedal application. Failure to verify can result in rear-end collision.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Reinstall any trim panels, bedliner clips, or protective covers removed during access
2. Verify no tools or fasteners were left in cargo bed or work area
3. Clean any fingerprints or debris from third brake light lens
4. Ensure wiring harness is secured and not hanging loose or contacting moving parts

Verification

• With ignition ON, press brake pedal and verify third brake light illuminates immediately and brightly
• Release brake pedal and verify third brake light turns off completely with no delay
• Repeat brake application test 5-10 times to confirm consistent operation with no flickering
• Visually inspect for proper gasket seal - no gaps visible between assembly and mounting surface
• Check for water intrusion by spraying mounting area with water and inspecting for leaks (if time and conditions permit)
• Verify no warning lights or brake system faults displayed on instrument cluster
• Road test vehicle and have another person follow to confirm third brake light is visible and functioning during actual brake applications
• MANDATORY: Complete final verification that third brake light operates correctly before returning vehicle to service

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