How to increase the headlight brightness on a Generation-1 Explorer:
My Gen-1 1994 explorer uses 9004 halogen bulbs, which only put
out around 700 lumens. I converted it to use 9007 halogen bulbs which
puts out around 1000 lumens.
A bulb swap from the OEM 9004's to the much brighter 9007's has
been discussed in various forums (including here in 2001) and
thought I'd write up a more detailed how-to guide. And determine
whether one needs to upgrade the entire wiring harness or not.
Plus see if the resulting beam pattern is okay with the stock reflectors.
Instructions:
1. Buy:
- New 9007 halogen bulbs.
( I used Silvania 9007XV bulbs. About $20/pair at Autozone. )
- 9004 or 9007 wiring harness. This three wire cable has a male
connector on one end, and a female connector on the other end,
and is about 6" long.
( I bought mine for $20. )
2. Remove existing headlight bulbs. Twist the lightbulb retaining ring
counterclockwise ( on back of headlight housing) about a 1/4 turn
while pulling on it. Pull out old lightbulb. Disconnect the wiring
connector from the bulb. The bulb has three wires going to it, low
beam (red/black), high beam (light green/black) and ground (solid black).
Save the bulbs if you want to go back to factory original. Be careful
not to touch the glass part of the bulb with your fingers as any
oil will dramatically reduce the bulb life.
3. Modify the purchased 9004/9007 wiring harness to reverse the low
beam wire and the ground wire. On the Racing Labs harness these are
the red and black wires. This is the wiring harness already
modified to reverse the red and black wires:
If you'd like to save the $20 for the harness you can either remove the
pins in the existing Ford connector and swap the red/black wire and
the black wire, or cut the two wires and swap them. I preferred to use
the separate adaptor harness so I could go back to factory original
if needed.
4. Cut the two keying tabs on the existing headlight housing - at the
5:00 o'clock position and the 8:00 o'clock position. I used a dremel tool.
You shouldn't have to remove the headlight housings in order to do this,
but may have to remove the battery.
5. Insert new 9007 bulbs. They will only go in one way and shouldn't
rotate around in the housing if you saved the last remaining keying
tab at the 12:00 o'clock position. Be careful not to touch the bulb
surface with your bare oily fingers. Twist on retaining ring. Plug in
adaptor harness. Looks like:
6. Reaim the headlights. The 9007 bulbs have differently oriented filaments
and the beam aim and pattern will be very different than the 9004's.
Especially in the vertical direction. Use a 4mm hex socket, or headlight
adjust tool. The vertical adjust screws are the long black shafts on the
outer edges of the headlight housings. Here's what my new beam pattern
looks like: (Actually better than the very scattered, very dim, original.)
You're done.
The geeky stuff:
The 9007 bulbs use 55 Watts, and the existing 9004 bulbs use only 45 Watts.
Since you're drawing 10 Watts more per headlight, the voltage drop in
the factory wiring is a bit higher. If the voltage drop is too much, the
9007 light output could actually be lower than the factory 9004's.
( A 5% drop in voltage lowers the light output of a halogen bulb by
almost 20%. ) To check this, I measured the voltage at the bulbs
before and after the mod. The voltage was about 2% lower. The 9007's
are still 30% brighter even with the slightly lower voltage at the bulbs.
If you want to go even brighter, you can always modify one or both of
the adaptor harnesses to include a relay and run a separate wire directly
to the battery. I chose not to do this to keep the install as simple as
possible. And, running the full battery/alternator voltage (14.4V) to the bulbs also
dramatically reduces the bulb life since they are spec'd to run at 12.8V.
A 12% increase in bulb voltage would increase the brightness 50%, but
reduce the life by 75%. Since the 9007XV's already have a shorter life than
the regular 9007's, I didn't want to cut that down even further.
Plus the new 9007 headlights are plenty bright now.
V @ Batt w/ engine running = 14.4 V
Original 9004, voltage at bulb:
Left = 13.0 V Right = 12.7 V
Estimated light output = 709 Lumens
New 9007 with factory wiring:
Left = 12.7 V Right = 12.4 V
Estimated light output = 935 Lumens
A 30% improvement in light output for less than $50.
My Gen-1 1994 explorer uses 9004 halogen bulbs, which only put
out around 700 lumens. I converted it to use 9007 halogen bulbs which
puts out around 1000 lumens.
A bulb swap from the OEM 9004's to the much brighter 9007's has
been discussed in various forums (including here in 2001) and
thought I'd write up a more detailed how-to guide. And determine
whether one needs to upgrade the entire wiring harness or not.
Plus see if the resulting beam pattern is okay with the stock reflectors.
Instructions:
1. Buy:
- New 9007 halogen bulbs.
( I used Silvania 9007XV bulbs. About $20/pair at Autozone. )
- 9004 or 9007 wiring harness. This three wire cable has a male
connector on one end, and a female connector on the other end,
and is about 6" long.
( I bought mine for $20. )
2. Remove existing headlight bulbs. Twist the lightbulb retaining ring
counterclockwise ( on back of headlight housing) about a 1/4 turn
while pulling on it. Pull out old lightbulb. Disconnect the wiring
connector from the bulb. The bulb has three wires going to it, low
beam (red/black), high beam (light green/black) and ground (solid black).
Save the bulbs if you want to go back to factory original. Be careful
not to touch the glass part of the bulb with your fingers as any
oil will dramatically reduce the bulb life.
3. Modify the purchased 9004/9007 wiring harness to reverse the low
beam wire and the ground wire. On the Racing Labs harness these are
the red and black wires. This is the wiring harness already
modified to reverse the red and black wires:
If you'd like to save the $20 for the harness you can either remove the
pins in the existing Ford connector and swap the red/black wire and
the black wire, or cut the two wires and swap them. I preferred to use
the separate adaptor harness so I could go back to factory original
if needed.
4. Cut the two keying tabs on the existing headlight housing - at the
5:00 o'clock position and the 8:00 o'clock position. I used a dremel tool.
You shouldn't have to remove the headlight housings in order to do this,
but may have to remove the battery.
5. Insert new 9007 bulbs. They will only go in one way and shouldn't
rotate around in the housing if you saved the last remaining keying
tab at the 12:00 o'clock position. Be careful not to touch the bulb
surface with your bare oily fingers. Twist on retaining ring. Plug in
adaptor harness. Looks like:
6. Reaim the headlights. The 9007 bulbs have differently oriented filaments
and the beam aim and pattern will be very different than the 9004's.
Especially in the vertical direction. Use a 4mm hex socket, or headlight
adjust tool. The vertical adjust screws are the long black shafts on the
outer edges of the headlight housings. Here's what my new beam pattern
looks like: (Actually better than the very scattered, very dim, original.)
You're done.
The geeky stuff:
The 9007 bulbs use 55 Watts, and the existing 9004 bulbs use only 45 Watts.
Since you're drawing 10 Watts more per headlight, the voltage drop in
the factory wiring is a bit higher. If the voltage drop is too much, the
9007 light output could actually be lower than the factory 9004's.
( A 5% drop in voltage lowers the light output of a halogen bulb by
almost 20%. ) To check this, I measured the voltage at the bulbs
before and after the mod. The voltage was about 2% lower. The 9007's
are still 30% brighter even with the slightly lower voltage at the bulbs.
If you want to go even brighter, you can always modify one or both of
the adaptor harnesses to include a relay and run a separate wire directly
to the battery. I chose not to do this to keep the install as simple as
possible. And, running the full battery/alternator voltage (14.4V) to the bulbs also
dramatically reduces the bulb life since they are spec'd to run at 12.8V.
A 12% increase in bulb voltage would increase the brightness 50%, but
reduce the life by 75%. Since the 9007XV's already have a shorter life than
the regular 9007's, I didn't want to cut that down even further.
Plus the new 9007 headlights are plenty bright now.
V @ Batt w/ engine running = 14.4 V
Original 9004, voltage at bulb:
Left = 13.0 V Right = 12.7 V
Estimated light output = 709 Lumens
New 9007 with factory wiring:
Left = 12.7 V Right = 12.4 V
Estimated light output = 935 Lumens
A 30% improvement in light output for less than $50.
