Replace the dimmer switch (lighting control module) located on the steering column of a 2016-2021 Honda Civic 1.5L Turbo, restoring proper headlight dimmer and turn signal functionality.

Warnings

Tools required

Parts

• Dimmer/multifunction switch assembly × 1 — Honda OEM 35256-TBA-A01 or equivalent

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn ignition to OFF position and remove key completely
3. Wait at least 3 minutes after turning off ignition before beginning work to allow airbag system capacitors to discharge
4. Disconnect negative battery terminal and isolate cable away from battery post
5. Adjust steering wheel to lowest and fully extended position for maximum access

Procedure

1. 1

   Remove lower steering column cover
   Locate and remove the two Phillips screws on the underside of the lower steering column cover. Gently pull the lower cover downward and away from the column, releasing the retention clips at the rear. Set cover aside carefully to avoid breaking mounting tabs.
   Torque spec

   Cover Screws10 Nm (8 lb-ft)
2. 2

   Remove upper steering column cover
   Remove the two Phillips screws securing the upper steering column cover. Carefully separate the upper cover by lifting upward and pulling forward to disengage the clips near the instrument cluster. Note the position of any wire harness clips attached to the cover before removal.
   Torque spec

   Cover Screws10 Nm (8 lb-ft)
3. 3

   Locate and access dimmer switch assembly
   Identify the dimmer switch assembly on the left side of the steering column. The switch is held by two mounting bolts accessible from the side and has a large electrical connector on the back. Note the routing of the wiring harness for reinstallation.
4. 4

   Disconnect electrical connector
   Press the locking tab on the dimmer switch electrical connector and carefully pull the connector straight back off the switch. If the connector is tight, gently wiggle it while pulling. Do not pull on the wires themselves. Inspect connector terminals for corrosion or damage.
5. 5

   Remove dimmer switch mounting bolts
   Using a 10mm socket, remove the two bolts securing the dimmer switch assembly to the steering column bracket. Support the switch assembly as you remove the second bolt to prevent it from falling and damaging wiring underneath.
   ⚠Keep track of bolt orientation and any washers or spacers; installation position affects switch alignment
   Torque spec

   Module Mounting Bolts8 Nm (6 lb-ft)
6. 6

   Remove old dimmer switch
   Carefully slide the dimmer switch assembly off the steering column, guiding it around any wire harnesses. Note the position of the alignment pin on the back of the switch that indexes into the steering column bracket.
7. 7

   Inspect and prepare installation area
   Inspect the steering column bracket for any damage or worn mounting points. Clean any corrosion from mounting surfaces with electrical contact cleaner. Verify the alignment pin hole in the bracket is clear of debris.
8. 8

   Install new dimmer switch assembly
   Align the new dimmer switch with the steering column bracket, ensuring the alignment pin on the back of the switch properly indexes into the hole in the bracket. Slide the switch assembly onto the column until it seats flush against the mounting surface.
9. 9

   Install and torque mounting bolts
   Install the two mounting bolts finger-tight, ensuring the switch remains properly aligned. Using a torque wrench, tighten both bolts to 8.0 Nm (6.0 lb-ft) in a cross-pattern to ensure even seating. Verify the switch operates smoothly through all positions without binding.
   Torque spec

   Module Mounting Bolts8 Nm (6 lb-ft)
10. 10

    Reconnect electrical connector
    Align the electrical connector with the back of the dimmer switch and push firmly until the locking tab clicks into place. Gently tug on the connector to verify it is fully seated and locked.
11. 11

    Reinstall upper steering column cover
    Position the upper steering column cover over the column, engaging the clips near the instrument cluster first. Press down firmly around the perimeter to seat all retention clips. Install the two Phillips screws and torque to 10.0 Nm (8.0 lb-ft).
    Torque spec

    Cover Screws10 Nm (8 lb-ft)
12. 12

    Reinstall lower steering column cover
    Align the lower steering column cover with the upper cover and column assembly. Press upward to engage the rear retention clips, then install the two Phillips screws and torque to 10.0 Nm (8.0 lb-ft). Verify both covers are flush and properly seated.
    Torque spec

    Cover Screws10 Nm (8 lb-ft)
13. 13

    Reconnect battery and initialize systems
    Reconnect the negative battery terminal and torque to 6.0 Nm (4.0 lb-ft). Turn ignition to ON position without starting engine. Check for any warning lights on instrument cluster related to lighting or steering systems.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Ensure all steering column cover screws are properly torqued and covers are flush with no gaps
2. Verify dimmer switch lever returns to center position after turn signal operation
3. If power windows do not auto-up/down, perform window initialization by fully opening then fully closing each window while holding the switch up for 2 seconds

Verification

• Turn ignition to ON position and verify instrument cluster illumination responds to dimmer control rotation
• Test headlight high/low beam operation by pulling and pushing the dimmer switch lever
• Verify turn signals operate correctly in both left and right positions with proper self-canceling function
• Test that hazard lights function with dimmer switch in neutral position
• Confirm flash-to-pass function works by pulling dimmer lever toward steering wheel
• Check that all steering column covers are secure with no rattles when moving steering wheel through full range of motion
• Verify no warning lights remain illuminated on instrument cluster after test cycle

More procedures for this vehicle