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Lots and lots of threads out there about LED headlights, some going cheap, some going expensive. Well here's a route I'll bet no one has taken so far. I've always been an E-code H4 guy, put them in most of my cars and this C4 is no different. I installed a set of Koito E-code headlamps with high quality H4 bulbs and have been pretty happy with them, but just wanted something brighter and whiter. So I started looking around and came up with the Phillips Ultinon H4 LED bulbs. These are a direct H4 drop-in bulb designed to work with standard H4 reflectors. So no, these will not work with your regular headlight setup since you have to have the H4 lamps first.
I installed them yesterday and I'm pretty happy with them, good light and brighter than the halogens I removed. There are still some uneven spots which is the Koitos reflector design, but overall I think it was a good upgrade.
Phillips Ultinon on the right, halogen H4 on the left. Low beam High beam
Question for you: Are your fog lights still functional? I put in Holley LEDs. and my fog lights are no longer working. I did some research and found out it has to do with the way a certain relay is grounded. The fix is to remove the right side knee bolster, find a light green wire on a relay, cut it and ground it to a different spot on the car (near glovebox). I'm learning that these cars have wiring that was designed for incandescent and not LED. As a result you're dealing with different voltages and resistances. When you start throwing modern, upgraded parts into the car, you can run into a host of unintended consequences.
I'm not sure I'm going to keep the LEDs. The low beams are OK but high beams hardly do anything. I've always loved the E-Codes and I may switch back. Although I sent an Email to Daniel Stern and received no response.
EDIT: I don't know if it matters, but your car is a 1994 and mine is a 1996. That might make a difference in how things work.
Last edited by Rogue One; Nov 30, 2025 at 01:07 PM.
Question for you: Are your fog lights still functional? I put in Holley LEDs. and my fog lights are no longer working. I did some research and found out it has to do with the way a certain relay is grounded. The fix is to remove the right side knee bolster, find a light green wire on a relay, cut it and ground it to a different spot on the car (near glovebox). I'm learning that these cars have wiring that was designed for incandescent and not LED. As a result you're dealing with different voltages and resistances. When you start throwing modern, upgraded parts into the car, you can run into a host of unintended consequences.
I'm not sure I'm going to keep the LEDs. The low beams are OK but high beams hardly do anything. I've always loved the E-Codes and I may switch back. Although I sent an Email to Daniel Stern and received no response.
EDIT: I don't know if it matters, but your car is a 1994 and mine is a 1996. That might make a difference in how things work.
Wow that is a timely post! No kidding, I was just about to post about the weird behavior after installing the LEDs. Yep the fog lights are not working, and it's stranger than that. The fog light switch turns on the high beams! Definitely an issue with the LED install, and I was starting to search for the problem. Thank you for the info, I'll dig in and see if I can get the problem fixed while keeping the LEDs. And I'll let you know what I find out.
So I did fix the high beam/fog light issue a while back, just never got around to posting about it. You have to pull the passenger side knee bolster and get to the relay block in front of the heater core. Back when I replaced the core, I really hoped I would never be in there again, and while this wasn't nearly as bad, there's a little PTSD there.... In any case, the idea is you have to ground one side of the fog lamp relay, which will restore normal functionality to the fogs and high beams. All of the writeups I saw said you ground the "green" wire, when they should say the light green wire. Yes there's a dark green one too (on a different relay), don't cut that one. The pic below shows the relay block and the wire you need to cut and ground, and this will fix the issue when you install LED headlights.
I really need to get back to this thread more often, but the truth is I haven't had much to do. The car has been just fantastic, daily driving and racking up the miles. Is there a better daily driver than a Corvette? I just crossed 55k, time to change the oil and air filter. Much easier job than on a C5...drain plug in the front of the pan, what the hell were they thinking? Anyway, when I did the air filter, I just pulled the housing out - much easier. And I noticed this on the underside of the housing. Pretty cool chrono impression with the Month, Day, Year and Shift. Hard to tell exactly what it's pointing to, but it's sometime in 1979. Anyone know what it means?
I have tinted the windows, hatch and put a film on the windshield, but the southern sun just through the glass roof just turns it into an oven in the summer. Adding this roof panel from Zip made a HUGE difference, way more tolerable when it's 90+ and it's parked outside. It's the type that has tabs that fit between the seal and roof panel, so it will be in there all summer. Once the temps cool off a bit, I'll take it back out and enjoy the roof again.
New tires! Toyo Extensa HP II not quite as high performance as the Contis I did have, but for the kind of driving I do (daily, all weather) they are much better. Quieter, don't follow grooves in the road, track straight and true, and the ride is just a little bit better. I live on a great set of mountain roads and after a couple hundred miles the mold compound is gone and the treads are scuffed in nicely, excellent grip on the curves too. And the price was right.
This is such a tough color to capture in the sun. The first pic does a pretty good job, but the full pics just don't do it justice. So I asked chatgpt to enhance it just a little and I think it turned out pretty well. Maybe a bit too bright, but it does bring out the color. Then for the hell of it, I had it install some different 18" wheels to see what they might look like.
Silver wheels are , imho, the best you can contrast with the Purple. Five Spokers and or Mesh , BBS style would be cool.
You're not wrong. I really wanted to see what bronze would look like and while I like it, I think either silver or gray would be the best. I like the 5 spokes, maybe in a gunmetal color.
I like the A Molds or Fikse five spoke. C4s look good with 17 and 18, 19s not so much. Its actually a pretty tiny car... Not quite Purple, but my 40th many years ago. Chrome or Silver with the Purple, Rubys, Dark Blues for example look great
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.
