Turn signal / directional bulb type
Mar 16, 2007, 01:50 PM
#1
Turn signal / directional bulb type
so i needed to change some turn signal bulbs, but its near impossible to find those WY21W bulbs that the service manual says to get. i read somewhere that you can use 7440 (W21W) bulbs as a replacement, but they need to be modified a bit. so i did a little research to find out what the differences between the two are, and then went and picked up a cheap 7440 to try a little experiment. WY21W and 7440 are exactly the same (both 3mm x 16mm) except for a very minor structural difference on the base of the bulb. the base of the 7440 just needs some minor "trimming" in a specific area. check out the diagrams below.
that jagged piece that sticks out in the diagram on the right (with the thick red circle and crappy arrow poiting at it) is the same on both bulb types, only it extends a little farther along the base of the bulb on the 7440. looking at the diagram on left, those pink hashes inside the other red circle represent the portion of the tab that needs to be shaved down. it doesnt have to be exact, i got it right the first time just by taking a little bit off. there are two of these tabs on each bulb, one on either side of the base. a dremel would be ideal for this shaving, but i used a sanding drill bit that i have. its just a bit with a cylindrical head wrapped in sandpaper, i got it in some kit that had a bunch of random bits. this may seem like too much to go through just for some stupid bulbs, but i make it seem more confusing than it is. it literally took me less than 2 min to shave it down.
Now for the good news. after i went through this process, and was all happy that i got the 7440 bulb to fit, i ordered some fancy bulbs that have a silver coating, but still glow amber (just so when u look at the heads or tails, u cant see the amber reflection...looks good actually). i dont like amber, but any other color really cant be seen during the day. so they get here and i notice that they are not an all glass bulb like most u buy in a store, but a glass bulb with a black plastic base that is smooth, without all those jagged tabs like in the diagram above. so before i flipped out, i simply tried to put one in my tail light...fits like a glove. i had to push a little hard to get it to snap in, but it wasnt a forcing push because i could pull it out with ease. they fit in the front also. i dont think i received the wrong bulbs, its probably just a different type of 7440 bulb that worked in my favor. i have an VIII (04) btw. so i know this was kinda lengthy for a simple directional bulb change, but its definetly a pain (and probably expensive) to find these WY21W for some people, so i know someone will get use out of this.
**To the mods: I know i cant list the website i ordered these bulbs from, but i feel that it would be very useful info for other members, since they will fit without any modification. So if theres any way to disseminate that info without breaking any rules, feel free to contact me for the site name. Also, i know this thread is borderline "How to" material, but i have only done this once and couldnt guarantee it will work for everyone...so take whatever action is necessary, i just felt this is a pretty useful FYI since everyone will have to change turn signal bulbs at one time or another. GL
-Al
that jagged piece that sticks out in the diagram on the right (with the thick red circle and crappy arrow poiting at it) is the same on both bulb types, only it extends a little farther along the base of the bulb on the 7440. looking at the diagram on left, those pink hashes inside the other red circle represent the portion of the tab that needs to be shaved down. it doesnt have to be exact, i got it right the first time just by taking a little bit off. there are two of these tabs on each bulb, one on either side of the base. a dremel would be ideal for this shaving, but i used a sanding drill bit that i have. its just a bit with a cylindrical head wrapped in sandpaper, i got it in some kit that had a bunch of random bits. this may seem like too much to go through just for some stupid bulbs, but i make it seem more confusing than it is. it literally took me less than 2 min to shave it down.
Now for the good news. after i went through this process, and was all happy that i got the 7440 bulb to fit, i ordered some fancy bulbs that have a silver coating, but still glow amber (just so when u look at the heads or tails, u cant see the amber reflection...looks good actually). i dont like amber, but any other color really cant be seen during the day. so they get here and i notice that they are not an all glass bulb like most u buy in a store, but a glass bulb with a black plastic base that is smooth, without all those jagged tabs like in the diagram above. so before i flipped out, i simply tried to put one in my tail light...fits like a glove. i had to push a little hard to get it to snap in, but it wasnt a forcing push because i could pull it out with ease. they fit in the front also. i dont think i received the wrong bulbs, its probably just a different type of 7440 bulb that worked in my favor. i have an VIII (04) btw. so i know this was kinda lengthy for a simple directional bulb change, but its definetly a pain (and probably expensive) to find these WY21W for some people, so i know someone will get use out of this.
**To the mods: I know i cant list the website i ordered these bulbs from, but i feel that it would be very useful info for other members, since they will fit without any modification. So if theres any way to disseminate that info without breaking any rules, feel free to contact me for the site name. Also, i know this thread is borderline "How to" material, but i have only done this once and couldnt guarantee it will work for everyone...so take whatever action is necessary, i just felt this is a pretty useful FYI since everyone will have to change turn signal bulbs at one time or another. GL
-Al
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