Chevrolet C20 Ignition Switch: A Guide for 1975-1987 Owners
Having trouble starting your Square Body truck? Your ignition switch might be the problem.
- The ignition switch is on the steering column under the dash, not where the key goes in.
- Symptoms often include no-start conditions, stalling, and flickering dash lights.
- Before replacing, check that the switch's mounting screws haven't just come loose.
- Choosing a higher-quality aftermarket brand like Standard Ignition may prevent premature failure.
Is Your C20's Ignition Switch Failing?
On a classic truck like the 1975-1987 Chevrolet C20, electrical parts wear out. The ignition switch is used every time you drive, and its internal contacts can degrade over decades of use. If you're experiencing strange electrical issues, there's a good chance this switch is the culprit.
Common Symptoms of a Bad Ignition Switch:
- No-Start or Intermittent Start: You turn the key and nothing happens, or it only starts after a few tries. Sometimes, you might have to turn the key further and further over time to get it to crank.
- Stalling While Driving: The engine might suddenly cut out, especially when hitting a bump. This is a serious safety issue caused by the switch momentarily losing connection.
- Accessory & Dash Light Problems: Your radio, wipers, or power windows might not work, or the dashboard lights may flicker on and off randomly. This happens because the switch isn't sending a steady power signal.
- Key Feels Loose or Won't Turn: While this can also be the lock cylinder, a worn-out switch can cause binding or a lack of resistance when turning the key.
- Truck Starts and Immediately Stalls: The switch may provide power to start the engine but fail to keep the ignition system powered in the 'Run' position.
Choosing the Right Aftermarket Ignition Switch
For a 1975-1987 C20, finding a new OEM ignition switch from GM is highly unlikely. The aftermarket is your primary source for this part. Quality can vary, so it's important to choose a reputable brand.
It's a common misconception that you need to remove the steering wheel to replace the ignition switch. The actual switch is a separate part from the key lock cylinder and is located further down the steering column. However, if your problems are related to the key itself (not turning, getting stuck), you may need to replace the lock cylinder, which is a more involved job.
🎬 Watch: How to replace the ignition lock cylinder and keysAftermarket Brand Tiers
| Brand | Our Assessment |
|---|---|
| Standard Ignition (SMP) | Standard Motor Products is a well-regarded aftermarket manufacturer with a long history. They are often considered a top-tier replacement part, with quality that can sometimes meet or exceed the original. For a critical component like an ignition switch, this is a trusted choice. |
| Rostra Powertrain | Rostra is another established aftermarket supplier. While not as widely discussed in forums as Standard, they produce a wide range of electronic components and are a solid mid-tier option for your truck. |
| Replacement | This is a generic or "white-box" brand. While it offers the most budget-friendly price, the quality and longevity can be inconsistent. Some owners in forums report premature failure with lower-cost aftermarket switches, sometimes within a year. This might be a good option for a temporary fix but could lead to doing the job twice. |
Known Issues for the 1975-1987 C20
While there are no specific recalls or Technical Service Bulletins (TSBs) for the ignition switch on this generation of C20 trucks, forum discussions reveal common failure points. Often, the plastic switch housing becomes brittle with age, or the internal contacts wear out, causing intermittent connections. Some owners report that the screws holding the switch to the column can come loose, causing misalignment and starting problems. Before replacing the switch, it's worth checking if these screws are tight.
Pro Tip: When replacing the switch, it's crucial to align the new switch's slider with the position of the key. The switch is often slotted to allow for adjustment. Mark the position of the old switch before removing it to make installation easier.
Frequently Asked Questions (FAQ)
Do I need to remove the steering wheel to replace the ignition switch?
No. The ignition switch is mounted on top of the steering column, under the dash. 🎬 See how to replace the switch on a non-tilt column You only need to remove the steering wheel if you are replacing the ignition lock cylinder where you insert the key.
Why does my truck only start in Neutral, not Park?
This is more likely an issue with your Neutral Safety Switch, which is a separate part, or its adjustment, rather than the ignition switch itself.
My key turns, but nothing happens at all—no click, no lights. Is it the switch?
It could be the ignition switch, but you should first check your battery and battery cables for corrosion or loose connections. If the battery is good, the ignition switch is a very likely suspect for a complete loss of power.
Is it hard to replace the ignition switch myself?
For a DIY mechanic, it's a manageable job, but can be uncomfortable. It requires working under the dashboard in a tight space. You'll likely need to lower the steering column by removing a few bolts to get access. The difficulty is generally considered low to moderate.
🎬 Watch: Step-by-step ignition switch replacement on a Squarebody truckAn aftermarket switch failed on me already. Is OEM better?
While original GM parts were robust, they are no longer available new for this model year. The quality of aftermarket parts varies greatly. Choosing a higher-quality aftermarket brand like Standard Ignition (SMP) is your best bet for longevity, as even they can sometimes source from the original equipment suppliers.
Helpful Videos
Technical Specifications
The ignition switch for the 1975-1987 C20 is a mechanical, sliding contact switch actuated by a rod connected to the key lock cylinder. It is mounted on the upper side of the steering column, under the instrument panel.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.