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1982-1990 GMC S15 Back Up Light Switch Guide and Part Review

If your reverse lights are out, the problem is often this simple, inexpensive switch located on your transmission.

3 minutes to read 1982-1990 GMC S15
Difficulty
2/5
Est. Time
0.5 hrs
DIY Doable?
✅ Yes
Shop Labor
$62-$95
⚠️ Drivable, but... — You can drive the truck, but it is a safety risk as others won't know you are reversing and you may get a traffic ticket.
Key Takeaways
  • The most common symptom of failure is reverse lights not working when the bulbs and fuse are good.
  • This is a simple DIY repair; the switch is located on the driver's side of the manual transmission.
  • ACDelco and Standard Ignition are top-quality brands for this part.
  • Before ordering, confirm you have a manual transmission, as automatic models use a different part.
The back up light switch on your 1982-1990 GMC S15 has one job: to turn on your reverse lights. It is a simple plunger-style switch mounted directly on the manual transmission. When you shift the truck into reverse, the shift linkage inside the transmission pushes on the switch's plunger. This completes an electrical circuit, sending power to the white lights on the back of your truck. This lets other drivers know you are backing up and helps you see in the dark.

Is Your Back Up Light Switch Failing?

A bad back up light switch is more than an annoyance; it's a safety hazard. Other drivers and pedestrians can't tell you're reversing, which is especially dangerous in parking lots. It can also get you a ticket. Before you assume the switch is bad, check two other things first: the reverse light bulbs and the fuse. If the bulbs are good and the fuse is intact, the switch is the most likely culprit. 🎬 Watch: 5 common reasons your reverse lights aren't working Sometimes, a bad switch can even cause the fuse for the turn signals to blow.

Symptoms of a Bad Back Up Light Switch

  • Reverse lights do not turn on: This is the most common sign of a failed switch.
  • Reverse lights stay on: The switch can fail in the 'on' position, leaving the lights on even when you're not in reverse. This will drain your battery.
  • Lights work sometimes: If you have to jiggle the shifter to get the lights to work, the switch is worn out and failing.

Manual vs. Automatic Transmission

This guide is for the back up light switch on manual transmission S15 trucks, which is located on the transmission case. Trucks with an automatic transmission use a combination Neutral Safety / Back Up Light Switch located on the steering column, which is a different part.

Choosing the Right Aftermarket Switch

For a simple part like this, you don't always need to pay for a part from the dealer. Aftermarket options offer good quality and value. Here’s a breakdown of the brands available.

Brand Tiers for Your S15

Premium Aftermarket (Best): ACDelco & Standard Ignition
ACDelco is General Motors' own parts brand, and their products are considered original equipment (OE) quality. For an older truck, an ACDelco part is as close to factory as you can get. Standard Ignition (Standard Motor Products) is a top-tier aftermarket manufacturer with a long-standing reputation for making reliable electrical parts that meet or exceed OEM quality. You can trust either of these brands for a long-lasting repair.
Value Aftermarket (Good): Replacement
The "Replacement" brand represents a category of budget-friendly parts. These switches are designed to be a direct fit and function like the original, but at a lower cost. For a simple switch on an older truck, this can be a perfectly acceptable option to get your lights working again without spending much.

Pro Tip: Check the Connector

Before ordering, take a quick look under your truck at the switch's electrical connector. Over decades, wiring can get brittle and corroded. If the connector or wires look damaged, it's a good idea to order a new pigtail connector along with your switch to ensure a solid connection.

Cost of Replacing Your Back Up Light Switch

Part Type Estimated Cost
New Aftermarket Switch $26.28 - $40.77
New OEM Switch (GM/ACDelco) $20 - $35
Shop Labor $62 - $95

Frequently Asked Questions

Where is the back up light switch located on a 1982-1990 GMC S15?

For manual transmission models, the switch is screwed into the driver's side of the transmission housing. 🎬 See this video to help locate the switch on the transmission You will need to safely get under the truck to see and access it.

Can I replace this switch myself?

Yes, this is a good DIY job for a beginner. The process involves safely lifting and supporting the truck, unplugging the electrical connector, and using a wrench to unscrew the old switch and install the new one. The most difficult part is often working in the tight space around the transmission.

🎬 Watch this step-by-step guide to replacing the switch yourself
What tools do I need to replace the switch?

You will need basic hand tools, including a wrench or socket set. The switch typically has a 7/8" hex head. Sometimes a standard socket is too long to fit, so a shorter sensor socket or a modified socket may be needed to get it out. You will also need a jack and jack stands to safely lift the vehicle.

Do I need to drain the transmission fluid?

No. The back up light switch is located high enough on the transmission case that you should not lose any significant amount of fluid when you remove it. Have your new switch ready to install quickly just in case a small amount of fluid weeps out.

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Technical Specifications

OEM Part Numbers: 14069600

Thread Size: M16 x 1.5, Connector: 2-Pin Female

Wrenchy
Article researched & written by
Go-Parts' AI research assistant. Every article is backed by live web research, verified OEM data, and real technician knowledge — so you get accurate, up-to-date information you can trust.
Meet Wrenchy → Updated Apr 19, 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.

Year Coverage
This article covers the Back Up Light Switch for:
  • GMC S15: 198219831984198519861987198819891990
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