H4 help

1990-964 · 02-27-2008, 01:32 AM

Hi guys!,

A little help from anyone that has converted to H4 headlights. First can anyone clue me into the wiring? I know that it is just three wires, but I can't get a handle on which terminal is which on the H4 bulb. Also the mounting is so different from the H5 setup. Does the H4 assembly really hold on with just one screw and the trim ring hooked onto the lip at the top of the light bucket? Any help is appreciated

Thanks

Rocket Rob · 02-27-2008, 07:09 AM

Hello,

You will love the the H4's. Yes, they are held on with a lip at the top of the assembly and then secured with a single screw at the bottom. I know it looks less than ideal but it seems to work well. Its been about 10+ years since I did converted to H4's so I can' give you specifics on the wiring. I seem to remember using trial and error to determine which was wire went where. Porsche uses brown wires for ground and will be the common wire for both the high and low beam circuits. I would put it at the center then try the other two on the sides. You will have a 50/50 chance of being right.

I hope this helps.

1990-964 · 02-27-2008, 10:14 AM

Rob,

Thanks very much, yes the info is helpful. You may not have been able to give me a difinitive answer on the wiring but knowing for sure about the mounting clears up that concern.

Regards,

Darren

pete000 · 02-27-2008, 12:42 PM

They make H5 to H4 adapters to make things easier.

altarchsa · 02-27-2008, 01:42 PM

Can anyone help me identify what I have? I understand original equipment was a sealed beam headlight? Is that an H5? My headlights have replaceable lamps (bulbs). Does that mean they are H4's?

I have cleaned the inside of the lights, but the reflective coating does not seem to be too good. And that must be general issue because I replaced one of the headlights with another used one and it is the same condition.

I have replaced the lamps with Silverstars. Low beam is OK, but high beam seems dangerously dark. Any ideas?

Sorry to barge in on your post 1990-964!

1990-964 · 02-27-2008, 05:15 PM

Pete,

Do you know of a source for those H5 to H4 adapters?

Altarcha,

If your headlights are U.S. spec then you have H5s, which I suspect you do because of the clouding of the lens, which they all seem to do. I believe it is because of the plastic reflector, and much like a plastic dash leaves a film on the inside of the windshield the plastic reflector most likely does the same to the lens. Both the H4 and H5 have replaceable bulbs. H4 lights for the 911s say H4 right in the center of the lens. The H4 bulb has a metal base held in place by spring clips,and the H5 bulb's base is plastic and held in place by a large plastic quarter turn star like retainer. Hope this helps.

Cupcar#12 · 02-28-2008, 04:18 AM

altrarchsa - if your lows are fine - the ground and high beam wiring may be reveresed - try that
(you won't blow anything) - i would do one at a time and get the leads hooked up correctly.
if i remember correclty - it was low-high-ground (not ground in the middle)
i am not near my car our i would take a picture for you.
but this might help with the headlight socket wiring

http://www.poweredbyzee.com/miata/he...conversion.gif

1990-964 · 02-28-2008, 10:13 AM

Well I now have it all together. Some of the input here and a healthy Google search provided everything I needed to complete the conversion.
For anyone attempting this, here is what you need to know. With the H4 bulb terminals facing you and the middle terminal up the left hand terminal is ground. The center terminal is the low beam and the right obviously is the high beam. On the H5 car plug side you will find brown which is ground, yellow which is the low beam and white which is the high beam. I made my own jumpers with crimp on connectors available at any electronics store. The light are great and really do a much better job of lighting up the road. They look much better too. Highly recomended, and the pair cost considerably less than one H5 replacement.

Colin 90 C2 · 02-28-2008, 10:20 AM

sorry I didn't see the post earlier, but pelican sells the h5-h4 adapter.
you will love the h4's. you can actually see where you're going at night.

altarchsa · 02-28-2008, 12:38 PM

Thanks 1990-C4 for researching the wiring.

And thanks to Cupcar#12. I'll bet you're right about my wiring. I'm pretty sure I put it back together the way it was when I cleaned the headlamps, but I never thought about the possibility that they may have been crossed when I got the car.

tbennett017 · 02-28-2008, 01:09 PM

Can you guys shed some light on the lens situation? I want to do the H4 conversion eventually (I have done it on every car I've ever had.. except the Audi that has HIDs)

Does the H5 glass assembly come out completely? Does the H4 have the same eccentric shape, just with a different bulb housing? Has anyone up-rated the bulbs with new relays for higher wattage?

Thanks.

1990-964 · 02-28-2008, 01:30 PM

The H4 and the H5 are completely different in every respect. The H5s mount to a frame that provides the adjustment of the light and it bolts to the headlight bucket. The H4 assembly is adjusted through screws in the retaining ring and mounts differently than the H5. It seems like the H5 mounting is much more solid as it bolts on in 4 places where as thre H4 is held on with only one screw and a lip at the top. It holds though and seems to be a proven design. All in all I really like them though.

Rocket Rob · 02-28-2008, 01:46 PM

Quote:

Originally Posted by tbennett017

Has anyone up-rated the bulbs with new relays for higher wattage?

Thanks.

I have higher watt bulbs. I installed relays and heavy duty wiring to handle it. I run 80/100W bulbs and they make a noticeable difference. I bought some spare bulbs recently and decided to try the 90/130's next. But I haven't tried them yet.

parsecnc4 · 02-28-2008, 03:00 PM

Quote:

Originally Posted by 1990-964

The H4 and the H5 are completely different in every respect. The H5s mount to a frame that provides the adjustment of the light and it bolts to the headlight bucket. The H4 assembly is adjusted through screws in the retaining ring and mounts differently than the H5. It seems like the H5 mounting is much more solid as it bolts on in 4 places where as thre H4 is held on with only one screw and a lip at the top. It holds though and seems to be a proven design. All in all I really like them though.

Do you have any pictures you can share?

ilko · 02-28-2008, 03:24 PM

Here's an installation guide from Pelican but it doesn't show the 964: http://www.pelicanparts.com/techarti..._headlamps.htm

02-27-2008, 07:09 AM	#2
Rocket Rob Addict Rennlist Member Join Date: Aug 2001 Location: Nashua, New Hampshire, USA Posts: 2,383	Hello, You will love the the H4's. Yes, they are held on with a lip at the top of the assembly and then secured with a single screw at the bottom. I know it looks less than ideal but it seems to work well. Its been about 10+ years since I did converted to H4's so I can' give you specifics on the wiring. I seem to remember using trial and error to determine which was wire went where. Porsche uses brown wires for ground and will be the common wire for both the high and low beam circuits. I would put it at the center then try the other two on the sides. You will have a 50/50 chance of being right. I hope this helps. __________________ Rob '90 C-4 Cab (daily driver-230K miles on original engine) '91 C-2 Coupe (weekend toy/DE car) '91 Honda Civic Si (winter-mobile)

02-27-2008, 12:42 PM	#4
pete000 Addict Rennlist Member Join Date: Dec 2003 Location: Rancho Palos Verdes CA Posts: 1,511	They make H5 to H4 adapters to make things easier. __________________ PCA Member since 1978 Current: 91 C2 Previous: 77 Lotus Esprit S1, 78 SC, 77 924, 82 924, 84 944, 84 Cab, 87 Coupe, 93 Corrado SLC, 03Boxster S.

02-28-2008, 04:18 AM	#7
Cupcar#12 Addict Rennlist Member Join Date: Apr 2002 Location: Sammamish, WA Posts: 2,252	altrarchsa - if your lows are fine - the ground and high beam wiring may be reveresed - try that (you won't blow anything) - i would do one at a time and get the leads hooked up correctly. if i remember correclty - it was low-high-ground (not ground in the middle) i am not near my car our i would take a picture for you. but this might help with the headlight socket wiring http://www.poweredbyzee.com/miata/he...conversion.gif __________________ Rob PCA Carrera Cup USA Registry www.carreracupusa.org Porsche's 92' Carrera Cup USA Edition #92012 59' 356A Coupe Land Rovers 08' LR3 Se 95' Defender 90 -all current- Kona Kope Coffee Company - 100% Kona Coffee Subscriptions -Owner 69' 912, 65' 356c, 90' 964 cab GP/Blue (#1008 Looking to buy this this one Still, PM me), 70' 911e, 69' 911s, 69 911e/s, 01' 986, 99' 996 Aero

02-28-2008, 10:20 AM	#9
Colin 90 C2 Addict Rennlist Member Join Date: Jun 2003 Location: Delaware Posts: 966	sorry I didn't see the post earlier, but pelican sells the h5-h4 adapter. you will love the h4's. you can actually see where you're going at night. __________________ 90 C2-GP White/Black,Gemballa primary muffler, drilled airbox,K&N, Roock/Bilstein, Lwt Flywheel, no drips 254 RWHP

02-28-2008, 12:38 PM	#10
altarchsa Addict Rennlist Member Join Date: Jul 2007 Location: Helotes, TX Posts: 409	Thanks Thanks 1990-C4 for researching the wiring. And thanks to Cupcar#12. I'll bet you're right about my wiring. I'm pretty sure I put it back together the way it was when I cleaned the headlamps, but I never thought about the possibility that they may have been crossed when I got the car.

02-27-2008, 01:32 AM	#1
1990-964 User Join Date: Sep 2006 Location: SF Peninsula Posts: 319	H4 help Hi guys!, A little help from anyone that has converted to H4 headlights. First can anyone clue me into the wiring? I know that it is just three wires, but I can't get a handle on which terminal is which on the H4 bulb. Also the mounting is so different from the H5 setup. Does the H4 assembly really hold on with just one screw and the trim ring hooked onto the lip at the top of the light bucket? Any help is appreciated Thanks

02-27-2008, 10:14 AM	#3
1990-964 User Join Date: Sep 2006 Location: SF Peninsula Posts: 319	Rob, Thanks very much, yes the info is helpful. You may not have been able to give me a difinitive answer on the wiring but knowing for sure about the mounting clears up that concern. Regards, Darren

02-27-2008, 01:42 PM	#5
altarchsa Addict Rennlist Member Join Date: Jul 2007 Location: Helotes, TX Posts: 409	Can anyone help me identify what I have? I understand original equipment was a sealed beam headlight? Is that an H5? My headlights have replaceable lamps (bulbs). Does that mean they are H4's? I have cleaned the inside of the lights, but the reflective coating does not seem to be too good. And that must be general issue because I replaced one of the headlights with another used one and it is the same condition. I have replaced the lamps with Silverstars. Low beam is OK, but high beam seems dangerously dark. Any ideas? Sorry to barge in on your post 1990-964!

02-27-2008, 05:15 PM	#6
1990-964 User Join Date: Sep 2006 Location: SF Peninsula Posts: 319	Pete, Do you know of a source for those H5 to H4 adapters? Altarcha, If your headlights are U.S. spec then you have H5s, which I suspect you do because of the clouding of the lens, which they all seem to do. I believe it is because of the plastic reflector, and much like a plastic dash leaves a film on the inside of the windshield the plastic reflector most likely does the same to the lens. Both the H4 and H5 have replaceable bulbs. H4 lights for the 911s say H4 right in the center of the lens. The H4 bulb has a metal base held in place by spring clips,and the H5 bulb's base is plastic and held in place by a large plastic quarter turn star like retainer. Hope this helps.

02-28-2008, 10:13 AM	#8
1990-964 User Join Date: Sep 2006 Location: SF Peninsula Posts: 319	Well I now have it all together. Some of the input here and a healthy Google search provided everything I needed to complete the conversion. For anyone attempting this, here is what you need to know. With the H4 bulb terminals facing you and the middle terminal up the left hand terminal is ground. The center terminal is the low beam and the right obviously is the high beam. On the H5 car plug side you will find brown which is ground, yellow which is the low beam and white which is the high beam. I made my own jumpers with crimp on connectors available at any electronics store. The light are great and really do a much better job of lighting up the road. They look much better too. Highly recomended, and the pair cost considerably less than one H5 replacement.

02-28-2008, 01:09 PM	#11
tbennett017 Addict Rennlist Member Join Date: May 2007 Location: Portland, Oregon Posts: 995	Can you guys shed some light on the lens situation? I want to do the H4 conversion eventually (I have done it on every car I've ever had.. except the Audi that has HIDs) Does the H5 glass assembly come out completely? Does the H4 have the same eccentric shape, just with a different bulb housing? Has anyone up-rated the bulbs with new relays for higher wattage? Thanks.

02-28-2008, 01:30 PM	#12
1990-964 User Join Date: Sep 2006 Location: SF Peninsula Posts: 319	The H4 and the H5 are completely different in every respect. The H5s mount to a frame that provides the adjustment of the light and it bolts to the headlight bucket. The H4 assembly is adjusted through screws in the retaining ring and mounts differently than the H5. It seems like the H5 mounting is much more solid as it bolts on in 4 places where as thre H4 is held on with only one screw and a lip at the top. It holds though and seems to be a proven design. All in all I really like them though.