electrical

Dimmer Switch

for 1970 AMC Rebel Machine 390ci V8 · RWD

Difficulty

Easy

Time

1.2 h

Tools

Steps

Replace the headlight dimmer switch, typically located on the steering column or floor, to restore high/low beam switching functionality.

Warnings

⚠Disconnect battery negative terminal before beginning work to prevent electrical shorts and accidental horn activation

ℹ️The dimmer switch on 1970 AMC Rebel is typically floor-mounted on the left side, not column-mounted like later models

Tools required

Phillips screwdriverEssential

Flat blade screwdriverEssential

Socket set (1/4" and 3/8" drive)Essential

Combination wrench setEssential

Test light or multimeter

Wire crimpers/strippers

Flashlight or work lightEssential

Parts

Dimmer switch × 1 — Use OEM specification or Standard Motor Products DS-61
Wire connector kit (if needed) × 1 — Assorted crimp connectors

Preparation

Park vehicle on level surface and engage parking brake
Disconnect negative battery cable and secure away from terminal
Allow engine to cool completely if recently driven
Ensure adequate lighting in driver footwell area
Note wire positions or take photo of switch connections before removal

Procedure

1
Access the dimmer switch
Locate the dimmer switch on the floor to the left of the steering column. Remove the floor mat and any trim pieces obstructing access. The switch is typically mounted to the floor pan with two screws and has a rubber boot covering the actuator rod.
2
Test current switch operation
Before removal, reconnect battery temporarily and use a test light to verify power at the switch terminals while operating the foot pedal. This confirms the problem is in the switch itself and not upstream wiring. Disconnect battery again before proceeding.
3
Disconnect wiring harness
Locate the wire connector leading to the dimmer switch. Press the locking tab and pull the connector straight off the switch terminals. If the vehicle has individual spade terminals instead of a plug connector, carefully note wire colors and positions before removing each wire.
4
Remove actuator rod connection
The foot pedal connects to the switch via an actuator rod. Remove the clevis pin or clip securing the rod to the switch lever. Swing the rod away from the switch to provide clearance for removal.
5
Remove mounting fasteners
Remove the two mounting screws securing the dimmer switch to the floor pan. These are typically 1/4" hex head screws or Phillips head. Support the switch while removing the second screw to prevent it from falling.
6
Remove old dimmer switch
Carefully lower the switch assembly from its mounting position and remove it from the vehicle. Inspect the mounting area for corrosion or damage that may have contributed to switch failure.
7
Prepare new dimmer switch
Compare the new switch to the old unit to verify correct replacement. Check that the mounting holes align and the actuator lever is in the correct position. If the switch has an adjustment feature, set it to the middle position before installation.
8
Install new switch
Position the new dimmer switch on the floor pan mounting location. Start both mounting screws by hand to ensure proper alignment before tightening. Tighten screws firmly but do not overtighten, as this can crack the switch housing.
9
Connect actuator rod
Reconnect the actuator rod from the foot pedal to the switch lever. Install the clevis pin and secure with the retaining clip. Verify the rod moves freely and the foot pedal returns to the up position smoothly.
10
Connect wiring harness
Reconnect the wiring harness to the dimmer switch terminals. If using a plug connector, ensure it clicks securely into place. If using individual spade terminals, match wire colors to their original positions and ensure connections are tight.
11
Test switch operation
Reconnect the battery negative cable. Turn the headlight switch on and test the dimmer switch by pressing the foot pedal. Verify that headlights switch between high and low beams smoothly. Check that the high beam indicator light on the instrument panel illuminates when high beams are selected.

Reassembly

Reinstall any floor trim pieces or panels removed for access
Replace floor mat in correct position
Verify foot pedal operation does not interfere with accelerator or brake pedals

Verification

With headlights on, press dimmer switch pedal and confirm smooth transition between high and low beams
Verify high beam indicator light on instrument cluster operates correctly
Check that switch pedal returns to up position when released
Ensure all electrical connections are secure with no exposed wiring
Confirm no interference between dimmer switch pedal and other foot controls