📋 Quick Facts
Time
45-90 min
Difficulty
Moderate
Tools
6 needed
Cost to DIY
$40-220
The ignition switch is the electrical part behind the key cylinder - the lock cylinder turns it to power on accessories, run, and start positions. Symptoms of failure: car will not start (no crank, no clicks), accessories cut out when turning the key, intermittent stalling, or the key will not turn at all (this is the lock cylinder, not the switch). On most cars the switch is held in the steering column with two screws.
🛠 What You'll Need
- New ignition switch (match year/make/model) (ignition switch on Amazon)
- Phillips and flat-blade screwdrivers (screwdriver set on Amazon)
- Torx bit set (T20-T30) (Torx bit set on Amazon)
- Trim removal tool set (trim removal tool set on Amazon)
- Multimeter (verify power at switch) (multimeter on Amazon)
- Painters tape and marker (label wires) (painters tape on Amazon)
⚠ When NOT to DIY thisWorking near the steering column means working near the airbag clockspring and wiring. A wrong move can deploy the driver airbag (broken nose, $1,000-2,000 repair). If your car has anti-theft (PATS, VATS, immobilizer) - common on most cars since 1998 - you may need a scanner relearn or a dealer visit after the swap. If your key will not turn at all, that is the LOCK CYLINDER (separate part) - and on many GM cars its replacement requires drilling. Different job entirely.
🔌 Expected Electrical ReadingsAt the ignition switch connector with key OFF: 12V on the constant battery feed pin. Key RUN: 12V on ignition feed pin. Key START: 12V on start feed pin (also energizes starter solenoid). Other pins are accessory and inputs - check the wiring diagram for your specific vehicle. A "good" key cylinder + bad switch shows 12V battery feed but no output in RUN/START.
✅ Before You Start - Checklist
- Park on level, solid ground (no slopes, no soft dirt)
- Engine is at the correct temperature (cold or warm as specified)
- All tools and parts on hand BEFORE you begin
- Owner's manual nearby for torque specs and locations
- Safety: gloves, eye protection, hood propped open
📝 Step-by-Step Instructions
- Disconnect the negative battery terminal and wait 5 minutesCritical - this is the only safe way to work near the airbag wiring. Five minutes lets the SRS module capacitor discharge.
- Lower the steering column or remove the cover panelsDepends on car: some have a removable lower dash panel, some need the column lowered with the tilt bolts loosened. Check your service manual.
- Remove the steering column shroudsUsually 2-3 Phillips screws underneath, then the upper and lower halves of the plastic shroud separate. Use a trim tool, not a screwdriver, to avoid scratching.
- Locate the ignition switchMounted on the column, just behind/below the key cylinder. Distinct from the cylinder itself - the switch is the electrical part with a multi-pin connector.
- Photograph the connector and wiringCritical reference - some plugs can be installed offset and cause symptoms identical to a bad switch.
- Disconnect the electrical connector(s)Usually one or two connectors. Press the tab, pull straight off. Tug lightly on each wire to ensure none are damaged.
- Remove the switch mounting screwsTypically two screws or one breakaway shear-bolt (older GM). If breakaway, you may need to drill or use locking pliers - this is where the job gets harder.
- Pull the switch off the columnIt should slide straight out once the screws are out. If it resists, double-check for hidden clips.
- Test the new switch BEFORE installingWith key in hand, turn the switch using a screwdriver in the slot. With a multimeter, verify continuity changes between positions (OFF/ACC/RUN/START). Saves you a re-do.
- Install the new switchAlign with the lock cylinder rod (or the slot, depending on design), thread the screws by hand. Snug, do not over-tighten.
- Reconnect the electrical connector(s)Push until click. Confirm orientation matches your photo.
- Reinstall steering column shrouds and dash panelsReverse of removal. Confirm all clips engage - rattles here come from missed clips.
- Reconnect the battery and testTurn the key through all positions: ACC (radio works), RUN (dash lights, fuel pump prime), START (engine cranks and starts). If anti-theft light blinks and the engine will not start, you need a key relearn procedure.
✅ After You Finish - Verify Checklist
- No tools left in the engine bay or under the car
- Test the system you worked on (start, drive, check, etc.)
- Look for leaks or drips after 5 minutes of running
- Record the date and mileage in your service log
- Recycle or properly dispose of any old parts/fluids
🔗 Related Guides
❓ Frequently Asked Questions
Ignition switch vs lock cylinder - which do I have?
Lock cylinder = the part the KEY goes into (turns or doesnt). Ignition switch = the electrical part behind it. If the key turns smoothly but nothing happens electrically, the switch is bad. If the key wont turn, the cylinder is bad.
Will I have to do an anti-theft (immobilizer) relearn?
Usually no - the switch itself is not key-coded. The immobilizer reads from a chip in the key head via an antenna ring on the lock cylinder. As long as you do not replace the cylinder or the antenna, relearn is not needed.
Why did my airbag light come on after?
You did not wait 5 minutes after disconnecting the battery, or you unplugged the SRS connector (yellow) by accident. A scanner-based airbag code clear and clock spring inspection is needed - take to a shop if you are unsure.
Can I just clean the old switch instead?
Sometimes. If the switch only fails intermittently, removing it and spraying electrical contact cleaner into the body, then working it through all positions 20 times can restore it. Replacement is more reliable.
My car cranks with a screwdriver in the switch - is the switch good?
Most likely yes. If hitting the START position with a screwdriver makes the car crank but the key does not, the issue is upstream (lock cylinder or the rod between cylinder and switch).
Do all cars use the same kind of switch?
No. GM uses key-on-column with separate switch and cylinder. Many Asian and European cars use push-button start with a separate ignition relay module - replacement procedure is very different. Always verify the part for your specific year/make/model.