What Size Bulbs Does a 1985 Isuzu Impulse 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 1985 Isuzu Impulse Have?
The 1985 Isuzu Impulse features an extensive lighting system with 12 bulb positions. It uses halogen technology with H4656 LED low beams and H4651 LED high beams in a dual-bulb configuration. The Impulse has been available from 1985 to 1992, and the 1985 model falls in the early-generation years.
Can You Put LED Bulbs in a 1985 Isuzu Impulse?
To upgrade the 1985 Isuzu Impulse headlights to LED, you will need a H4656 LED LED kit for the low beams and a H4651 LED LED kit for the high beams. Start with the low beams since they are used most often and have the biggest impact on nighttime visibility. For the fog lights, a LED Fog Light LED bulb provides a clean white output that pairs well with LED headlights.
How to Replace Bulbs on a 1985 Isuzu Impulse
To remove the headlight bulb, disconnect the wiring harness, then twist the bulb counter-clockwise and pull it straight out of the housing. Older model years like the 1985 Impulse typically offer easy access to the headlight bulbs from behind the headlight assembly under the hood. Most owners can complete the swap in under 10 minutes per side. When installing the new bulb, avoid touching the glass with bare fingers. Skin oils create hot spots that shorten bulb life. Wear clean gloves or handle the bulb by its plastic base only. The fog lights are accessed from underneath the front bumper. You may need to remove a few plastic clips or screws from the fender liner to reach the LED Fog Light fog light socket.
Full Upgrade Bundle
Upgrade All 12 Positions at Once
1985 Isuzu Impulse Complete Bulb Size Chart
| Position | Bulb Size | Shop |
|---|---|---|
Low Beam | H4656 LED | Buy H4656 LED |
High Beam | H4651 LED | Buy H4651 LED |
Fog Light | LED Fog Light | Buy LED Fog Light |
Brake Light | 158 | Buy 158 |
Side Marker | 194 LED | Buy 194 LED |
Turn Signal Front | 1157 LED | Buy 1157 LED |
Turn Signal Rear | 1073 LED | Buy 1073 LED |
Reverse Light | 1073 | Buy 1073 |
Dome Light | DE3022 | Buy DE3022 |
License Plate | 194 | Buy 194 |
Parking Light | 1157 | Buy 1157 |
Trunk Light | LED Light | Buy LED Light |
Want to upgrade everything at once?
Shop Complete LED Kit for 1985 Isuzu ImpulseHow Long Do 1985 Isuzu Impulse Headlight Bulbs Last?
Standard halogen headlights on the 1985 Isuzu Impulse have an expected lifespan of 500 to 1,000 hours, which works out to roughly 2 to 3 years of normal use. Signs of a failing halogen bulb include noticeably dimmer output, a yellowish tint compared to the other headlight, or intermittent flickering. At 41 years old, the original bulbs on your Impulse are likely overdue for replacement. Even if they still illuminate, reduced brightness significantly impacts nighttime safety. When one headlight burns out, replace both sides at the same time. Bulbs from the same batch age at similar rates, and mismatched brightness is distracting to oncoming drivers.
What Bulbs Are Compatible with the 1985 Isuzu Impulse?
The H4656 low beam bulb on the 1985 Isuzu Impulse is a specific fitment. There are no widely recognized cross-compatible alternatives, so make sure to purchase the exact H4656 size. Using the wrong bulb size can cause improper beam patterns that reduce your visibility and blind other drivers. It can also cause overheating inside the headlight housing, potentially warping the plastic lens or reflector. Always verify the bulb number before purchasing.
1985 Isuzu Impulse Headlight FAQ
Did Isuzu Impulse Bulb Sizes Change Over the Years?
Over its production run from 1985 to 1992, the Isuzu Impulse has seen bulb size changes in the Low Beam, High Beam and Brake Light positions. The 1985 model uses the earlier bulb specification that was in place before the change around 1988. Always verify the exact bulb size for your specific 1985 model year using the chart above, as using the wrong size can result in poor fitment or reduced light output.
Other Impulse Years
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Other Vehicles That Use H4656 LED Bulbs
These vehicles from other makes also use a H4656 LED low beam bulb: