UK3 is the RPO code for steering wheel mounted controls — the buttons on the spokes. GM’s wording for it has shifted between “steering wheel audio controls” and the broader “steering wheel controls”, and our records hold both.
It matters for one reason above all others: if you are changing the radio, UK3 decides whether you need an interface module to keep the buttons working.
Where UK3 is documented
| Year | How GM described it | Source |
|---|---|---|
| 1997 | “Control, steering wheel, accessory” | GM option master |
| 2022 | “Steering wheel audio controls” | Secondary order-guide transcription only |
| 2025 | “Steering wheel audio controls” and “steering wheel controls” | GM Fleet order guides |
| 2026 | “Steering wheel controls” and “steering wheel audio controls” | GM Fleet order guides; GM Canada eOGLD |
Twenty-six GM-sourced records. Note that 2025 and 2026 both carry two wordings at once — that is two GM documents describing the same code slightly differently in the same year, not a change in what the code means. Our decoder shows both rather than picking one.
Why UK3 decides your radio install
On a truck with UK3, the buttons do not talk to the radio directly. They sit on a resistive ladder or a data bus and the factory head unit knows how to read them. Fit an aftermarket radio and that conversation stops.
The fix is a steering wheel control interface — a small module wired between the wheel circuit and the new radio. It is inexpensive and it works well, but you have to know you need one before you buy the radio kit, because the interface is usually a separate item.
If your label has no UK3, there are no buttons to preserve and you can skip that module entirely.
Buttons, wheel and cruise are three codes
| Code | Covers |
|---|---|
| UK3 | The controls on the spokes |
| NK5 | The urethane rim |
| NP5 | The leather-wrapped rim |
| K34 | The cruise control system behind the cruise buttons |
From 2022 GM’s K34 description says “steering wheel-mounted”, which blurs the line on modern trucks. On older ones the separation is real: a truck can have UK3 audio buttons and no cruise at all.
If the buttons stopped working
On a factory radio, dead steering wheel buttons are usually one of three things, in order of likelihood:
- The clockspring. It carries every circuit that crosses from the column to the rotating wheel, and it wears. Horn and airbag warning problems alongside dead buttons point straight at it.
- The switch pack itself. These are resistive and they drift with age and moisture.
- A connector behind the wheel that was disturbed during other work.
Check in that order rather than replacing the radio.
How to check yours
- Look at the spokes. Buttons mean the hardware is there; whether it works is a separate question.
- Decode UK3 for your model year, and run the whole label so you also pick up the wheel code and K34.
- If the wheel was swapped by a previous owner, the label will not match what you see. Believe the truck, not the sticker, and check the clockspring before you order parts.
Sources
- 2025–2026 GM Fleet order guides; GM Canada eOGLD order guide
- GM VPPS option master, November 2002
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