1987-1991 GMC V3500 Back Up Light Switch: A Complete Guide
If your reverse lights are out, this guide will help you diagnose and replace the right switch on your classic GMC V3500 truck.
- The most critical step is ordering the correct switch: one type is for automatic transmissions (on the steering column) and a different one is for manual transmissions (on the transmission case).
- Always check the bulbs and the 'TURN B/U' fuse before replacing the switch.
- For automatic transmissions, the new switch may need to be adjusted on the steering column to work correctly.
- Standard Ignition is a reputable aftermarket brand known for quality, while 'Replacement' brands offer a budget-friendly alternative.
Is Your Back Up Light Switch Failing?
A faulty back up light switch is a common problem on these durable trucks, but the symptoms are usually straightforward. Before you blame the switch, always check the simple things first: make sure the reverse light bulbs aren't burned out and check the fuse, which may be labeled "TURN B/U" or similar in your fuse panel. On some models, this fuse is shared with the turn signals, so if your turn signals are also out, the fuse is a likely culprit. If the bulbs and fuse are good, the switch is the next part to inspect.
Symptoms of a Bad Back Up Light Switch
- No Reverse Lights: The most common sign of failure. When you shift into reverse, the lights do not come on at all.
- Intermittent Lights: The lights flicker or only work when you wiggle the gear shifter. This often points to a worn internal contact or a misaligned switch, especially on automatic models.
- Reverse Lights Stay On: Less common, but the switch can fail in the 'on' position, keeping the reverse lights lit even when driving forward, which can confuse other drivers.
Choosing the Right Aftermarket Switch
For a vehicle of this age, original GM parts are often discontinued. The aftermarket offers reliable replacements, but you must buy the correct part for your transmission type.
- For Automatic Transmissions: You need the combination Neutral Safety / Back Up Light Switch. This is a larger, half-moon shaped part that mounts to the steering column under the dashboard.
- For Manual Transmissions: You need a smaller, screw-in style switch that threads directly into the transmission housing.
When it comes to brands, you have a couple of tiers to consider:
- Premium Aftermarket (e.g., Standard Ignition): Brands like Standard Motor Products (SMP) are well-regarded by professional technicians for their quality and durability. Choosing a premium brand can provide peace of mind and a longer service life.
- Standard Aftermarket (e.g., Replacement): These are often private-label brands that offer a direct fit and function at a lower price point. They are a cost-effective solution that will get the job done.
| Brand Tier | Price Range |
|---|---|
| Standard Ignition | $28 - $32 |
| Replacement | $26 - $29 |
Note: Prices are estimates and may vary based on the specific part for your transmission and the retailer.
Frequently Asked Questions (FAQ)
Where is the back up light switch located on my V3500?
It depends entirely on your transmission. For an automatic, look for a crescent-shaped switch on the steering column, under the dashboard near the firewall. For a manual transmission, you will need to get under the truck and find the screw-in switch on the transmission case, often on the driver's side or top.
Can I replace this switch myself?
Yes, this is a very DIY-friendly job for most owners. For automatic models, you'll be working in the tight space under the dash. For manual models, you'll need to safely raise and support the vehicle on jack stands to access the transmission. The job typically requires basic hand tools and should take less than an hour.
Does the new switch need to be adjusted?
For manual transmissions, no adjustment is needed. For automatic transmissions, the switch on the steering column is adjustable. After installing the new switch, you may need to loosen the mounting screws and rotate it slightly to ensure the reverse lights only activate when the gear selector is in the 'R' position.
My lights still don't work after replacing the switch. What now?
If a new switch, fuse, and bulbs don't solve the problem, the issue is likely in the wiring. On a 30+ year-old truck, wires can become brittle, corroded, or broken. Check for power at the switch's electrical connector and inspect the wiring harness for visible damage. Also, check the ground wires at the tail light housings, as a bad ground can prevent the lights from working.
Were there any recalls for the V3500 back up light switch?
No, searches of the National Highway Traffic Safety Administration (NHTSA) database did not find any recalls specifically for the back up light switch on the 1987-1991 GMC V3500.
Technical Specifications
OEM Part Numbers: 14069600 19152823 14014559 15566155
Varies by transmission type. Automatic transmission switches are typically crescent-shaped and mount to the steering column. Manual transmission switches are typically a 2-pin, screw-in design that mounts directly to the transmission.
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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.
- GMC V3500: