not really an upgrade then is it :>) It is a known issue and is not recommended. The bulbs are very different.
Technical bulletin: 9004 & 9007 bulbs.
9004 and 9007 Bulbs
What are the differences? They look interchangeable- but they're not.
When should I use 9007 bulbs?
Use 9007 bulbs in headlamps marked "DOT HR HB5" and wherever a 9007 was the original bulb
When should I use 9004 bulbs?
Use 9004 bulbs in headlamps marked "DOT HR HB1" or "DOT HR" and wherever a 9004 was the original bulb.
The 9004 (HB1) bulb, introduced in 1983, was the first halogen
bulb available for use in North America. It uses 12 Volts, has a
45 Watt low beam filament producing 700 lumens, and a 65 Watt high beam
filament producing 1200 lumens. These filaments are transverse-if you hold the
bulb upright, they run across the bulb
from side to side.
The 9007 (HB5) bulb, introduced in 1992, uses 12 Volts, has a 55 Watt low beam filament
producing 1000 lumens, and a 65 Watt high beam filament producing 1350
lumens. These filaments are axial-if you hold the bulb upright, they run along the
from top to bottom.
9004 and 9007 bulbs are keyed differently, so they can't be interchanged, but
the higher light output of the 9007 tempts some people to try making 9007 bulbs fit
in headlamps designed for 9004 bulbs
This is not an upgrade, and it's unsafe.
It's important to use the specified bulb
Each headlamp is designed to use only one type of headlamp bulb. It may be a
9004, a 9007, or some other type. Headlamps are optical instruments, and they
depend on the filament being very precisely oriented and placed exactly how
and where it's supposed to be, in order to form a beam pattern with the right
amounts of light in the right places.
If the filament is improperly oriented or placed because the wrong kind of bulb
is used, the headlamp's optics won't see what they're expecting to see, and they
won't be able to do their job. The result will be a damaged beam pattern that
won't provide safe seeing light for the driver, andwill cause blinding glare for other road users.
Please don't use 9007 bulbs in housings designed for 9004 bulbs.
9004 to 9007 headlight bulbs ' Ford Explorer and Ford Ranger ...
https://www.explorerforum.com > ... > Modified 1991-1994 Explorers
Dec 20, 2012 - Basically, the filament position of the 9007 bulb lights up the high beam portion .... I am now having an issue where my highs dim and the dash high indicator stays on 24/7. ... (CORRECT ANSWER) Change the bulbs to the correct 9004. ... I could barely see my beams on the ground before, and now I have ...