Three months ago, my 1987 F-250’s headlights were a joke. Two dim 5×7 sealed beams that painted the road like a dying flashlight. I wanted a modern 2.5 inch bi led projector retrofit, but every guide online felt either too vague or too salesy. So I bought a set of GTR 2.5 bi led projector headlights from www.rhgtr.in, cleared my weekend, and learned the hard way. This is the exact walkthrough I wish I had—warts, mistakes, and all.
Why a 2.5 Bi-LED Projector Retrofit? (Spoiler: It’s Not Just Brightness)
A proper 2.5 bi led projector retrofit transforms your beam from a vague glow into a surgical line of sight with a crisp cutoff. But I didn’t want a generic LED bulb inside a reflector housing—that just blinds everyone. The 2.5 inch bi led projector lens is the goldilocks size: small enough to fit most 4×6 or 7-inch round housings, but large enough to produce serious width. After reading 40+ forum threads, I realized that 2.5” hits the sweet spot between a tiny 2.0” (too narrow) and a bulky 3.0” (hard to aim).
What You Actually Need (Not the Store’s “Kit” List)
I ordered the GTR 2.5 inch bi led projectors set. Here’s what came in the box versus what I had to buy separately. Learn from my under-preparation.
- In the GTR box: Two complete projector assemblies (lens, LED chips, driver, cooling fan), mounting brackets, H4/9007 adapter plates, and a detailed wiring diagram. Plus shroud rings.
- What I forgot (and ran to the hardware store for): Butyl sealing tape (3/8 inch), a dremel with cutting wheels, self-vulcanizing rubber tape, a 2-inch hole saw, and a heat gun (not a hair dryer—trust me).
- Optional but smart: A set of “Morimoto RetroRubber” gaskets. The included ones worked, but the premium gaskets sealed better on my old housings.
The 6-Hour Process: From Baked Open to Buttoned Up
I worked slowly. A pro could do this in 3 hours. Here’s the real timeline and each gotcha.
Step 1: Baking the Headlight (Yes, In Your Kitchen Oven)
Set your oven to 200°F. Remove all bulbs and rubber seals from the housing. Place the headlight on a baking sheet lined with cardboard. Bake for 12 minutes—no more. I did 15 minutes on the first one and the plastic began to warp. After baking, use a flathead screwdriver to pry the lens from the housing. Work slowly. The old butyl glue will be stringy. Wear gloves; it’s hot.
Step 2: Removing the Old Reflector and Shaving the Bucket
Inside my sealed beam, there was a massive metal reflector bowl. This must be removed entirely. I used a dremel to cut three tabs holding it. Then came the surprise: the 2.5 inch bi led projector lens was 0.25 inches too long to fit with the rear cap on. So I had to cut a 2-inch hole in the back of the housing using a hole saw. This allows the fan and driver to stick out. Don’t panic—you’ll cover this hole with a rubber grommet later.
Pro tip from my mistake: Measure the total depth of the GTR projector (from lens front to fan rear) before cutting. My first hole was too low, and the projector aimed at the sky. Mark the centerline of the housing with a sharpie, then drill.
Step 3: Mounting the 2.5 Bi-LED Projector Using the Centering Ring
The GTR kit includes a self-centering aluminum ring. Slide the projector through the front hole of the housing, then thread the ring from the back. Tighten with the included spanner wrench. Do not over-tighten—aluminum threads are strong, but the housing plastic is not. I added a dab of blue threadlocker to the nut. This prevents the projector from vibrating loose over potholes. For a 2.5 bi led projector retrofit, a loose projector means a useless beam pattern.
Step 4: Wiring – The Only Scary Part (But Simple)
The GTR driver has three wires: red (battery positive), black (ground), and a white trigger wire (to your factory high beam signal). I used the included relay harness to pull power directly from the battery. Why? Because the factory 1987 wiring cannot handle the 35W per side. Without the relay harness, my headlight switch got hot enough to melt. Use the harness. Splice the white wire into the positive wire of your factory high beam bulb. Now, when you flash high beams, the 2.5 inch bi led projector headlights switch to high beam mode (a solenoid moves a shield inside the projector).
- Red wire: To battery positive (fused).
- Black wire: To chassis ground (sand the paint).
- White wire: To factory high beam positive.
Step 5: Bench Test Before Sealing (Crucial!)
Connect the setup to a 12V battery on your workbench. Turn on low beam. You should see a sharp horizontal cutoff with a slight 15° kick up on the passenger side. Turn on high beam—the cutoff should disappear, and the full LED power floods out. If you see flickering, check the ground connection. If the solenoid doesn’t click, check the white trigger wire polarity. I had reversed my trigger wire and spent 20 minutes panicking before realizing the simple fix.
Step 6: Final Sealing – Don’t Rush This
Clean the old butyl glue off both the lens and the housing. Use isopropyl alcohol. Then apply a new bead of butyl sealing tape around the channel. Press the lens back on. Put the housing back in the oven at 200°F for 8 minutes. Remove and clamp it using spring clamps (not C-clamps, which crack plastic). Let it cool for an hour. I skipped this cooling wait on my first light and the lens shifted. Patience pays.
Real-World Result: Beam Shots and Night Test
After reinstalling the headlights into the truck, I aimed them following the standard 25-foot rule: mark the center of the low beam hot spot on a wall, then park 25 feet back and adjust the vertical screw until the cutoff is 2 inches below the mark. The result? The GTR 2.5 inch bi led projector lens throws a wide, even carpet of light. No dark spots. No blinding oncoming traffic. The high beam reaches at least 400 meters down a rural straight. I took photos with my phone (attached below as proof).
“First night drive: I actually saw a deer standing 200 feet ahead and stopped in time. My old lights would have shown me a pair of eyes one second before impact.” — My own journal entry.
Common “People Also Ask” Questions (With Real Answers From This Retrofit)
Do I need to modify my headlight housing for a 2.5 inch bi led projector?
Yes, in most sealed beam or reflector housings, you must remove the internal reflector bowl and often cut a rear opening for the projector’s length. If you have a projector-style housing already, it may bolt in with adapters.
Can I use a 2.5 bi led projector lens with my factory H4 connector?
The GTR kit includes a universal H4/9007 adapter pigtail. However, for full performance, use the included relay harness to pull direct battery power. The factory wiring is only for the trigger signal.
What is the actual color temperature of the 2.5 inch bi led projectors?
The GTR units output 5500K—a clean, neutral white. It’s not the cheap 6500K “ice blue” that washes out in rain. I drove through a downpour and the 5500K cut through the wet asphalt reflections much better than my friend’s 6000K LEDs.
How do I aim a 2.5 bi led projector retrofit after installation?
Park on level ground 25 feet from a wall. Measure from ground to the center of your projector lens. Mark that same height on the wall. The top of the low beam cutoff should be 2 inches below that mark for both headlights. Adjust the vertical screw on your headlight housing. No screw? You’ll need to shim the mounting brackets with washers.
Will a 2.5 inch bi led projector overheat inside a sealed housing?
Only if you block the cooling fan. My GTR projector has a rear-mounted maglev fan. The 2-inch hole I cut allows hot air to exhaust. Do not seal the rear of the projector. Some people add a small breather vent; I just left the rubber grommet slightly loose. 30,000 miles later, no fogging or overheating.
Cost Breakdown vs. Buying Pre-Retrofit Headlights
| Option | Cost (USD) | Quality of Parts | Time Required |
|---|---|---|---|
| Pre-retrofitted lights (eBay/Amazon) | $250 – $450 | Unknown generic projectors, often poor sealing | 0 (bolt-in) |
| GTR 2.5” Bi-LED Kit (www.rhgtr.in) | $189 | Genuine Osram chips, copper cooling, aluminum mounts | 5-6 hours |
| HID projector retrofit (older tech) | $150 + ballasts | Slower warm-up, higher power draw, bulbs degrade | Similar 5 hours |
I chose the DIY route because I wanted to know exactly what was inside my headlights. No mystery components. Plus, the 2.5 inch bi led projector lens from GTR has a 24-month warranty through www.rhgtr.in—the pre-built sets usually offer 30 days.
Should You Do This Retrofit? The Honest Take
If you enjoy a Saturday project, own a heat gun, and can follow wiring diagrams, this is deeply satisfying. The difference between factory halogens and a 2.5 bi led projector retrofit is like upgrading from a candle to a surgical light. But if you don’t own basic tools or you’re nervous about cutting your only headlight housing, pay a local shop. For everyone else: order the GTR kit from www.rhgtr.in, clear your workbench, and follow this guide. One night of work yields years of safe, confident driving.
👉 Ready to start your retrofit? Get the same GTR 2.5” Bi-LED Projector set I used at www.rhgtr.in. Mention code “F250RETRO” for a free set of butyl sealant rolls (while stock lasts).