2021-2026 Cadillac CT4 & CT5 Combination Switch: Decoding Options for a Perfect Match

Part Function and Critical Compatibility Clarification

The combination switch on the 2021-2026 Cadillac CT4 and Cadillac CT5 is the stalk assembly on the side of the steering column that controls turn signals, wipers, and headlights. It is a common point of confusion, but this part is NOT directly related to the Super Cruise™ driver-assist system. The buttons to activate and control Super Cruise are located separately on the face of the steering wheel itself.

Because this part integrates multiple functions, a failure can manifest in various ways, often making it seem like the car has several unrelated electrical problems.

Symptoms of a Failing Combination Switch

When the combination switch begins to fail, you will typically notice problems with the functions it directly controls. While widespread failures on the CT4 and CT5 have not been commonly reported in owner forums yet, the symptoms are consistent with failures on other modern vehicles.

• Turn Signal Malfunctions: This is the most common symptom. The turn signals may not activate at all, work only intermittently, or fail to cancel after a turn. In some cases, only one side will work.
• Headlight and High Beam Issues: You might find that the headlights flicker, don't turn on, or you're unable to switch between low and high beams. Activating a turn signal might even cause the headlights to turn off momentarily.
• Windshield Wiper Problems: The wipers may not turn on, get stuck on a single speed, or operate randomly without you touching the stalk. The windshield washer function may also stop working.
• Warning Lights on Dash: A faulty switch can send erratic signals to the BCM, potentially causing incorrect indicator lights on the dashboard, such as a turn signal indicator that stays lit.

Known Issues, TSBs, and Recalls

As of early 2026, there are no active recalls from the National Highway Traffic Safety Administration (NHTSA) for the combination switch on the 2021-2026 Cadillac CT4 or CT5.

Some owners have experienced a range of complex electrical issues, but these are not typically traced back to the combination switch itself. A notable Technical Service Bulletin (TSB) that causes confusion is PIC6443A. This TSB addresses an issue with an "S165 Infotainment Control Switch" where a software problem prevented replacement parts from being programmed. It's important to know that the S165 switch is the control knob on the center console for the radio/display, not the combination switch on the steering column.

Buying a Used Combination Switch

Purchasing a used OEM combination switch is a cost-effective and reliable repair strategy, as factory parts often have better build quality and a more precise feel than cheaper aftermarket alternatives. However, careful verification is essential.

1. Verify Vehicle Options: The single most important step is to match the switch to your car's features. For vehicles like the CT4 and CT5 (2018 and newer), you can find the Regular Production Option (RPO) codes on a QR code sticker located on the driver's side door jamb. Scan this QR code with your phone to get a list of all options your car was built with. Match these codes to the donor vehicle's options.
2. Physical Inspection: Check the used switch for any signs of physical damage. Ensure the stalk moves smoothly through all its positions without sticking. Inspect the plastic housing for cracks and make sure the electrical connector pins are straight and free of corrosion.
3. Check Markings and Labels: All the white markings for the different functions should be clear and not worn away. Sometimes, part numbers are stamped or labeled on the switch body; if visible, try to match these numbers.
4. Mileage and Condition: A switch from a low-mileage vehicle is always preferable. Since this is a high-use component, one from a car with over 100,000 miles may have significant internal wear.

Cost of Replacement

Replacing the combination switch is relatively inexpensive, especially if you perform the labor yourself. Below is a breakdown of typical costs.

Replacement Difficulty: 2/5

Replacing the combination switch is a straightforward DIY job for someone with basic tools and patience. No special programming is required for the switch itself.

Estimated Time: 1 hour

Tools Needed: Screwdriver set (Phillips and flathead), trim removal tools, socket set.

General Steps:

1. Disconnect the Battery: Always disconnect the negative battery terminal before working on any electrical components.
2. Remove Steering Column Covers: 🎬 Watch this guide on removing the steering column covers. The plastic shrouds around the steering column are typically held by a few screws (often from the bottom) and plastic clips. Remove the screws and carefully use a trim tool to pry the upper and lower halves apart.
3. Unplug and Remove the Old Switch: 🎬 See how to safely remove a turn signal switch. The combination switch is usually held in place by one or two clips or screws. Depress the retaining clip on the electrical connector to unplug it, then release the switch from its mount on the steering column.
4. Install the New Switch: 🎬 Follow this walkthrough to install your new replacement switch. Snap the new switch into place, connect the electrical harness, and reassemble the steering column covers. Reconnect the battery and test all functions (signals, lights, wipers) to confirm the repair.

Frequently Asked Questions