H5 to H4 headlight conversion

[Steve 82SC]

I found the 9004 bulb base connectors at Auto Zone, but I've since seen them at Pep Boys. The H5 and H4 connectors are basically the same, but not identical. The H4 connectors have a thicker and more pronouced spade connector. The ones I found at Auto Zone had heavier gauge wiring than stock and had a rubber boot that slid up and over the entire connection once everything was plugged in. On each of the Auto Zone connectors, one wire was black, one red, and one green. The black goes to your brown ground and each of the other wires goes to a high beam side and the other to the low beam side. The aftermarket connector also had about 4-6 inches of wiring already in place. All you have to do is wire the new connector in the same configuration as what's already attached to the existing H5 connector. It will be very obvious when they're facing the same way and you're comparing the existing bulb connector and the one you've just purchased. The new one will have the same three receptacles for spade connectors, but they will be 90 degrees toward one another. Twist, solder, and shrink wrap and you're done.

I have a dark car with polished wheels and was going to purchase two primered H4 trim rings and paint them. However, when I installed the H4s with the chrome ring, I really thought it looked good and went along nicely with the wheels. The chrome also blends in with the entire headlight lens, so it doesn't stand out very much at all.

My original intention was to go with brighter bulbs since I already had a Sucro relay in place. Once I got the H4s installed, I found that the upgrade wasn't necessary. It wasn't that my H5lighting was dim, it was just an awful pattern of light through the DOT-compliant lens. The pattern of light with the H4 lens was an unbelievable improvement. But, I live in an urban area and the lack of street lighting has never been an issue. I might have increased the wattage if I lived in a more rural or suburban setting. But when I've been on a dark road with the new H4s, they performed admirably because of the drastically different pattern of light. I had previously changed my stock fogs for look-alike Hella 450 driving lamps. This really lights things up and uses the stock wiring from the original fog lights which oddly enough, unlike the headlights, has a relay in the circuit from the factory.

Steve

[Steve 82SC]

And don't forget Milt's suggestion to tether the H4 assembles to the inside of your headlight bucket. Those trim rings have been known to pop off with just the right bump. If you wire tie the headlight assembly to one of the now unused screw holes in the headlight bucket, you won't lose the entire assembly if a trim ring pops off the fender. You'll feel even worse when you run over it.

Steve

[summers3d]

Wow Steve, great information. Exactly what I was looking for. I have a dark colored car and got the H4's with the black ring. Hopefully it will blend in well. I'll post pictures when I'm finished.
-David

[ianc]

You can get primered trim rings instead of chrome. Get some and have them powder-coated, then cleared. When you're mounting them and trying to get the bucket screwed on using that one lousy screw at the bottom, you'll be glad you dd instead of just having them painted...

ianc

[purplehaze]

You guys ROCK! Thanks for all the great info.

Steve, you gave good advice, and cracked me up with the painful thought of running over the thing.....

Jeremy, thanks for the pictures, and hey, great color car! I used similar custom paint to do my engine bay, so I'll definitely do the trim rings IF I do this whole thing.

Thanks for the link to the prior post with wiring phots. That will help immensely.

Thanks guys!

- Glenn