the bulbs in my z06 have lasted me over 2 years. i have never had to replace the bulbs. so i look in the manual and it says the low beam is a 9006 and the highbeam is a 9005 bulbs.

I take the bezel off and proceed to take the bulb out expecting to see two bulbs like it shows in the manual. to my surprise there was only one bulb and it was a 9003 bulb.

I bought this car from its original owner with 14000 miles. what do you think happend... he must have rewired it right... what would be the reason to rewire it to accept a 9003 bulb.

 

It appears the previous owner may have installed the European glass headlamps, they are a single bulb headlamp versus the plastic original two bulb US version. The 9003 may be a higher wattage bulb, 55watt low/80 watt high. You can probably check the bulbs out at the Sylvania website. Try PFYC.com they sell a European conversion kit, they should have more information there.

 

^^^^^^^^

i dont know much about the euro conversion, but that sounds about right to me.

 

The EURO T-84's are a single H-4 bulb and all glass housing. No way to convert from/to stock bulbs.

 

is an h4 the same as a 9003 bulb?

 

No, not even close

 

I have T85s (dip left). Its a single dual filament bulb that fits in a single housing.

It uses an H4 bulb for the low wattage fit and PIAA 135/90s for the high wattage mod.

The only mod I'd heard of up to now was the mod to fit 9005 bulbs (hi beam) into the low beam housings.

 

thats odd you guys say the h4 and 9003 are different sizes. I was at pep boys today looking at both bulbs and the 9003 and h4 sockets look identical. i asked a guy on ebay about his h4 bulbs and he told me that the 9003 bulbs are the same as h4... i could see were he would be lieing to make the sale though. just from my observation at pepboys the sockets on the h4 and 9003 bulbs looked the same.

 

I stand corrected. Good call:

http://candlepowerinc.com/pdfs/H4_9003.pdf

"In 1991, automakers wanted to use H4 headlight bulbs on cars in the US, but the DOT decided engineering blueprints for H4 bulbs allow too much variance in the position of the filaments within the
bulb. So a new blueprint was made, with all the electrical and dimensional properties the same, but with stricter limits on filament placement variance. Because of the limits in the US on beam intensity in
effect in 1991, the maximum allowable light output tolerance was also reduced. This new bulb specification was called “9003/HB2”, because at the time, two numbering conventions were in use.
Many 9003/HB2 bulbs also carry the “H4” marking, and vice versa, because it is possible to meet the specifications in both blueprints at the same time."

 

So back to the original question

Why would a dual filament bulb be fitted into a stock housing? Using stock wiring the low and high beam circuits are seperate; one connector for each. The Euro harness combines the two to give low and high on a single pigtail with a 3 way connector. It would need to be a one off lead to allow both filaments to light on the same low beam circuit retaing a seperate high beam function.

What housings do you have, stock or Euro? It sounds to me like you may have T84s fitted.

 

^^^^

I bought this car used last year and it was bone stock... atleast thats what the original owner told me. The first poster told me he thinks he did the euro spec headlight swap.

I know the housing only houses one bulb and the wiring is all wired up for one 9003/h4 bulb in each housing. I am going to take a closer look tomorrow to see if the actual lenses are glass.

I am pretty sure the original owner did the euro swap.

 

Sorry, I didn"t know of that change either, my last dealings W/H-4"s until now, was pre 90's for off road lighting

 

yeah they are the euro housing.

changing the bulbs is a pain in the ***... any tips on changing the bulbs. someone told me that the headlight have to be half way up... i honestly dont see how that helps with the bulb swap.

 

Sounds like he did just that. You can tell by the faceting on the lens of the Euro which shapes the beam.

Stock lenses have a housing for each bulb (hi 7 lo) and are plastic. You can see from my pic above that the Euros have the single housing with the dual filament bulb. He probably fitted the harness as well which plugs in at the passenger side and takes the low bulb power feed and splits the funtions out into low and high beam.

 

Not had the problem yet but they do look to be in tight. I fitted my lights and left the H4s in. I plan to put the PIAA hi wattage ones in once the Vert gets back to UK.

 

Here is a recommendation on changing the bulbs:

Raise your headlamps via the switch on the stalk, with headlamps raised and on, turn the stalk to the parking lamp position. The headlamps will remain up, the headlights will go off, but the parking lamps will remain lit. Don't worry about those, they will go off in about 10 minutes automatically.

There are three phillips screw heads that hold the black surround bezel. One on the outboard side and two on the inner side. Remove all three screws. Carefully raise the hood, make sure that the bezels are not in the way of the hood when it opens. To remove the bezel pull gently from the upper middle above the headlamp (it slides into a clip above the headlamp), pull the upper part out about an inch and push down on the lower left and right corners. The bezel will drop right out.
This next part is optional, but if you have big arms it will help. There are two hood supports with black bumper stops located just inboard of each head lamp. They support the front lip of the hood. They have a black bumper on top, and threaded bolt into the front facia. Mark the location of the locking nut with a pencil or pen. Back off the locking nut and remove the bolt/bumper. Once removed its a clear shot to the rear of the headlamp assembly. Before removing the bulb, take a look at the current connectors placement, this will help ensure you put the new bulb in correctly. Change out your bulbs, make sure you don't touch the new bulb glass, wear latex gloves if necessary.

Put everything back together, check for proper alignment. (if possibile, before you remove the old lamps, you might want to mark on the garage wall, or door your current headlamps light pattern with masking tape to verify same pattern after installing the new lamps)

Good luck, take your time and you should have this done in less than an hour.

 

The problem with the Euro asembly is its a lot more substantial than the stock assembly. Its slightly deeper from the face to the rear of the housing so the bulbs sit in a lot tighter. Also the position of the single bulb makes it harder to get at.


Euro


Stock

Its doable but its a PITA. You could always loosen the mounting bolts if you have thick arms. I can just about do it but its tight.

I agree that taking off the black plastic housing is essential.

 

Yeah i normall just put the headlights up, take off the black plastic and just reach in and change them. It takes awhile because you cant see what your doing but rather feeling around. I can change both bulbs in about 30mins... its just a pain in the ***.

Anyone know how long a hid bulb last?