What is the low beam headlight bulb size for a 1988 GMC C3500?

The 1988 GMC C3500 uses a H4703 bulb for the low beam headlights. We recommend upgrading to LED for better visibility.

What is the high beam headlight bulb size for a 1988 GMC C3500?

The high beam bulb size for the 1988 GMC C3500 is H4701.

Why are my 1988 GMC C3500 headlights dim?

Dim headlights on a 1988 GMC C3500 can be caused by aging halogen bulbs, which lose brightness over time, or oxidation (cloudiness) on the plastic headlight lenses. Upgrading to a H4703 LED conversion kit can provide a significantly brighter and whiter light output.

Which bulb fits the 1988 GMC C3500 fog light?

The 1988 GMC C3500 typically does not come with factory fog lights in all trim levels. If your vehicle is equipped with them, check the manual as sizes can vary by trim.

Is the 1988 GMC C3500 single or dual beam?

The 1988 GMC C3500 uses a dual bulb headlight system. This means you have separate bulbs for high and low beams.

Can I install LED bulbs on my 1988 GMC C3500?

Yes, the 1988 GMC C3500 comes with standard halogen bulbs from the factory, but they can be upgraded to LED. You will need a H4703 LED conversion kit for the low beams.

Did the 1988 GMC C3500 change headlight bulb sizes from the previous year?

Yes — the 1988 GMC C3500 uses different bulb sizes than the 1986 model. The 1988 generation introduced this bulb configuration.

Is the 1988 GMC C3500 the first or last year to use H4703 bulbs?

The 1988 GMC C3500 is the only year in the 1988 generation to use the H4703 bulb for the low beam headlight.

How do I change the headlight on a 1988 GMC C3500?

Turn off the vehicle and open the hood. Locate the headlight assembly from behind, remove the dust cover or retaining clip, disconnect the wiring harness, twist the old H4703 bulb counter-clockwise to remove it, then insert the new bulb and reassemble. The whole process typically takes 10 to 30 minutes per side depending on accessibility.

Are LED headlights legal for a 1988 GMC C3500?

LED bulbs used off-road or in auxiliary lights are legal everywhere. For on-road headlight use, legality varies by state. Many states allow LED retrofits as long as the beam pattern meets DOT standards. For the best legal compliance, choose a DOT-approved H4703 LED kit that is designed as a direct replacement and produces a proper cutoff pattern without excessive glare.

How much does it cost to replace 1988 GMC C3500 headlights?

A pair of halogen H4703 bulbs costs $15 to $40, while LED conversion kits run $25 to $60 per pair. If you have a shop do the work, expect an additional $20 to $50 in labor per bulb. Replacing them yourself at home saves the labor cost and usually takes under 30 minutes.

What is the difference between halogen and LED for a 1988 GMC C3500?

Halogen bulbs produce a warm yellow light (around 3200K), last 500 to 1000 hours, and draw more power. LED bulbs emit a brighter white light (5000-6000K), last 25,000+ hours, and use less energy. LED upgrades for the H4703 position are available as direct plug-and-play replacements.

The 1988 GMC C3500 has a unique bulb configuration not shared with adjacent model years.

Fitment Guaranteed for 1988 GMC C3500

What Size Bulbs Does a 1988 GMC C3500 Use?

Correct headlight, fog light, and tail light bulb sizes. Sourced from OEM catalog data.

Installation Difficulty

Easy (Plug and Play)

Est. Replacement Cost

$15 - $40 (Halogen) / $30+ (LED)

What Lighting System Does the 1988 GMC C3500 Have?

The 1988 GMC C3500 utilizes a refined lighting configuration featuring 5 distinct bulb positions. It features a standard lighting system powered by a dual-bulb halogen configuration using separate H4703 low beam and H4701 high beam bulbs for precise light distribution. This model belongs to the mid years of the C3500's 1979-2000 production span.

Can You Put LED Bulbs in a 1988 GMC C3500?

For a GMC built for the road and trail, LED upgrades provide the high-contrast lighting needed for better obstacle detection. We recommend starting your upgrade with the H4703 low beams, as they see the most use. Adding a matching H4701 LED kit later will complete the look and ensure consistent lighting performance.

1988 GMC C3500 Bulb Size Chart

Position	Bulb Size	Shop
Side Marker	194	Buy 194 →
High Beam	H4701	Buy H4701 →
Low Beam	H4703	Buy H4703 →
License Plate	194	Buy 194 →
Reverse Light	1156	Buy 1156 →

How do the 1988 GMC C3500's bulbs compare to other years?

The 1988 GMC C3500 changed bulb sizes from 1986. The previous model year used a different configuration.

The 1989 model switched to a different bulb configuration.

This bulb configuration covers the 1988 model years. ← 1986 1989 →

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Other C3500 Years

2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1986 1985 1984 1983 1982 1981 1980 1979

Other Vehicles That Use H4703 Bulbs

1994 Pontiac Sunbird 1991 Chevrolet Full 1991 Chevrolet V3500 1990 Chevrolet C3500 1990 Chevrolet K2500