CONVERTING FROM 7" HEADLIGHTS TO H5 LIGHTS
Due to U.S. regulations, earlier 928s weren't able to have the same 8 inch headlights used
on models sold elsewhere in the world. The non-U.S. 8 inch lights are called "H4" lights and have a
distinct light pattern which is considerably brighter and sharper than 7 inch lights. Beginning with the
1987 model 928, U.S. cars used a different 8 inch light: the "H5". While still much brighter than the
7 inch lights, H5s are not as sharp or bright as H4s. I obtained a set of H5s (which are less expensive than
the rarer H4s and installed them on my 928 to take advantage of their better illumination and to get rid
of the silly chrome rings that accompany the 7 inch lights.
Here's a picture of the standard 7 inch light with the chrome ring.
Here's an H5 and an H4 side-by-side. You can see the H4 has a distinctive diagonal cut to the lense on the right.
A close-up of the H4, again showing the diagonal lense pattern.
The backside of the H4 shows that it has the same mounting features as a 7 inch light. If
you swap an H4 in, no wiring changes are necessary.
The plug assembly on an H5 is totally different. You'll need to cut the plug end off the car's harness
and splice it to the new H5 plug.
Start by turning the key to the "on" position. Turn the headlights on to raise them, turn off the key, and then turn off
the headlights. They should remain in the "up" position but not be illuminated. You can then
remove the three screws that hold the headlight cover in place.
Remove the headlight cover and put it aside.
With the headlight cover off, you can see the headlight assembly.
Unplug the headlight.
Remove the 4 screws that hold the assembly to the headlight control arm.
Pull apart the ball/socket joint that holds the bottom of the light assembly in place. Remove the light
and set it aside.
Here's a picture of the 7 inch light assembly. You can see how it resembles the H4 assembly's plug.
Now comes the wiring part. Since I had one H4 light and I wasn't sure whether I would eventually get another
one and get rid of the H5s, I wanted to be able to easily swap them out. Normally, you'll want to cut, splice and solder
the H5 plug to the car's wiring. Instead, I've opted to use some plug ends to make the swapping process easier.
Here you can see (1) the male plug ends attached to the H5 plug, and (2) those plug ends with some electrical tape. I used
the electrical tape just as an added precaution against dirt and debris getting in to the wire connections. I did the same
thing to the harness wiring, but using the female end adapters.
Now it's time to put the H5 light onto the headlight arm. First, re-attach the ball-and-socket joint
at the bottom of the headlight assembly.
Next, attach the headlight with the 4 mounting screws.
Attaching the wiring can be tricky. The wiring on the harness is easy enough: the wires are colored yellow, white and brown.
However, the H5 plug's 3 wires were all colored black. I obtained a picture of another H5 wiring assembly that allowed
me to identify each wire based on its orientation to the H5 plug itself:
The headlight is connected and secured. At this point I turned the headlights on and turned the key
to make sure they lit up. They did. The highbeams also worked normally.
I repeated the process on the other headlight and put both covers back on.
With both covers on and both lights working, I retracted the lights. Done!
