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1979 GMC G2500 Neutral Safety Switch: A Comprehensive Guide

If your 1979 G2500 won't crank or the reverse lights are out, the neutral safety switch is a likely and fixable culprit.

3 minutes to read 1979-1979 GMC G2500
Difficulty
2/5
Est. Time
1 hrs
DIY Doable?
✅ Yes
Shop Labor
$100-$150
Used OEM Price
$20-$40
⚠️ Drivable, but... — You can drive if it starts, but if it allows starting in any gear, it is a critical safety risk and should be fixed immediately.
Key Takeaways
  • A no-crank, no-start condition on a 1979 G2500 is very often a bad neutral safety switch, not the starter.
  • The switch is located on the steering column under the dash and is a feasible DIY replacement.
  • Proper adjustment after installation is required to make sure the van starts only in Park/Neutral and the reverse lights work.
  • New aftermarket parts from brands like Standard Ignition are the only practical replacement option as new OEM parts are unavailable.
On your 1979 GMC G2500 with an automatic transmission, the neutral safety switch is a critical safety device mounted on the steering column inside the cab. Its primary job is to prevent the engine from starting unless the gear selector is in Park or Neutral. This stops the van from lurching forward or backward unexpectedly when you turn the key. Additionally, this same switch is responsible for activating your reverse lights when you shift into the Reverse gear.

Is Your 1979 GMC G2500 Refusing to Start?

A common issue on a classic 1979 GMC G2500 is a no-start, no-crank condition. You turn the key, the dashboard lights up, but the engine doesn't even try to turn over—no click, no sound. Before you blame the starter or the battery, the neutral safety switch should be a primary suspect. On these older GM vans, the switch is a frequent point of failure due to age and use. A classic test is to hold the key in the 'start' position and slowly move the shifter between Park and Neutral. If you find a 'sweet spot' where the engine cranks, the neutral safety switch is almost certainly the problem.

Symptoms of a Failing Neutral Safety Switch

  • No Crank or Intermittent Start: The most common symptom where the engine won't crank at all, even though your lights and radio work.
  • Starts in Neutral, But Not Park: The van starts correctly when the shifter is in Neutral, but won't start when it's in Park (or vice-versa). This is a tell-tale sign of a misadjusted or failing switch.
  • No Reverse Lights: If your backup lights are out and you're also having starting issues, the switch is the likely cause.
  • Starts in Any Gear: A dangerous condition where the switch has failed and allows the engine to start in Reverse or Drive. This requires immediate replacement.

Choosing the Right Aftermarket Switch: Standard Ignition

For a vintage vehicle like the 1979 G2500, finding a new original equipment (OEM) neutral safety switch is practically impossible. The market is served by aftermarket manufacturers. Standard Ignition is a well-known and widely available brand for this part. Owner feedback suggests that while Standard Ignition parts generally work, some minor fitment issues can occur on these older GM columns. For example, one user noted having to slightly spread the new switch to fit it over the steering column. Despite potential minor adjustments, it is a reliable and cost-effective choice for getting your van back on the road safely.

Cost of New Aftermarket Neutral Safety Switch

Brand Price Range
Standard Ignition $53.37

Installation Pro-Tip

The neutral safety switch is located on the steering column, under the dashboard. Replacement is a straightforward job for a DIY mechanic. The key to a successful replacement is proper alignment. The new switch must be installed and adjusted while the gear shifter is in the Neutral position. Many new switches come with a small pin or clip to hold them in the neutral position for installation. After tightening the mounting screws, you must test that the van starts ONLY in Park and Neutral and that the reverse lights work correctly before reinstalling the lower dash panels.

Frequently Asked Questions (FAQ)

Where is the neutral safety switch located on my 1979 G2500?

It is located inside the van's cab, mounted to the upper part of the steering column, under the dashboard near the firewall. You will need to remove the lower dash cover to access it.

Can I just bypass the neutral safety switch?

While it is technically possible to bypass the switch by connecting the two large purple wires that go to it, this is strongly discouraged. Doing so creates a major safety hazard, as it will allow your van to start in any gear, potentially causing it to lurch unexpectedly and lead to an accident.

Are there any recalls for the neutral safety switch on this van?

No. Searches of the National Highway Traffic Safety Administration (NHTSA) database show no specific recalls for the neutral safety switch on the 1979 GMC G2500.

Do I need special tools to replace this switch?

Basic hand tools are all that's required. A 9/32" or 7mm socket or wrench is typically needed for the switch's mounting screws. You may also need tools to remove the lower dash panel, which often involves Phillips head screws and 5/8" nuts holding the column support.

Technical Specifications

Mounts to the steering column with two screws. Features two separate electrical connectors: one for the starting circuit (typically two large purple wires) and one for the reverse lights (typically green and blue wires).

Wrenchy
Article researched & written by
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Meet Wrenchy → Updated Apr 10, 2026

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.

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