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This article deals specifically with converting the two airhead rear turn signals into running lamps, while retaining the original turn signal function. Much is applicable to the FRONT. In my mind this conversion ADDS to safety, not only do you get more rear facing lights, but you have two lights that are lit in case your one stock running lamp burns out.

Some have arguments against this conversion, the primary argument is that the turn function is less noticeable to car drivers....due to the running lamp function. You must decide for yourself. Also, the conversion may not be legal if the lens is not recolored to be RED. NOTE that many bikes have only ONE rear running light...if it fails...you are INVISIBLE to cars coming up to your rear!!!!...which is an argument FOR this conversion.

I won't get into the legalities, that may vary state to state, but this conversion is believed legal if done correctly. For the REAR turn signals, I have used red lens material that Roy Truelsen provided on the first 'new style' conversion I did, so that following vehicles see red, but to the side is still the yellow of the original plastic covers. If the bulb does not touch the red plastic material, I found that almost any common red plastic material that will pass light, perhaps 1/16" or less thick, will do well. Hobby stores often have small bits and pieces of colored plastic sheeting. I did a lot of these conversions, years ago, withOUT adding the red material. Even very flexible thin red material is OK.    You might also use a red lacquer or other plastic compatible coating on the inside of the amber plastic lens....but only on the extreme rear, not the sides of the plastic lens, and this is, of course, only for REAR turn signal lenses. ...I have done that 'painting' on a lot of these conversions.

NOTE #1: Much of this information is also applicable to the front turn signals. The turn signals on the stalks models are very similar, front and rear. The turn signals in the RS and RT fairings are different, but the sockets similar.. Thus, one may use much of the following information to convert the front turn signals. BUT...for the front turn signals, while they CAN be converted in a similar way, I have also used a method in which I drilled the reflector and installed a very small lamp in its separate small socket, sideways. That was an experiment. I really do prefer the conversion of the socket as described below. Obviously, for the front's, you do NOT use red material or paint.   The front socket and setup is different for the faired versus unfaired models. But, the principle is exactly the SAME. You may have to run a wire to them...on the RT, perhaps from the eyebrow light...whatever, it is very simple.

NOTE #2: I did contemplate making the rear turn signal housings 'all function'...that is, incorporating a few diodes to make them act as run and turn; but, with diodes, adding a brake light function. I never did the engineering work, although it most likely can be done.

This article sounds complicated, but isn't. Please read it through a few times before doing anything.   I DO want you to remove the outer plastic lens cover over your taillight and over the turn signals, pull the innards out just a bit, and LOOK at things!    READ this procedure through, as you look at these areas.

NOTE that the plastic lens covers should NOT have their mounting screws overtightened...if you go at that with too much force, you will break the lens. Note also, that SOME plastic lens covers can only be installed in one direction. A drain area is usually provided on the lower edge. SOME can NOT be installed with the TOP marked area on top...that is normal.

Using the 1157 (2157) bulb with its offset pins is a FAR better choice than non-offset types like 1176. More on the 1176 later herein. Using a common 1157 (2157) lamp ENSURES that, if properly wired at the socket, you will have a BRIGHT turn signal, and considerably dimmer running lamp, which is what you want....AND...bulb replacement is easy.

When this was originally announced on the Airheads LIST, Roy used a PS34240 numbered part for the socket. That is a Borg Warner product number. Pep Boys and other places sell Borg Warner. However, when I purchased the Borg Warner part, it was part number PT11 in their catalog. It was a tad nicer than the Napa part, which was Echlin brand #LS6538, but that will also work just fine.

What you are going to do is modify the stock bulb 'socket/reflector', which is one unit, to accept a metal socket with two contacts for a #1157 (2157) lamp. That lamp can fit into the socket in only one position, due to the offset pins on the #1157 (2157) lamp (as opposed to the 1176). You are going to modify the socket/reflector carefully, and ream the existing hole or otherwise make it slightly larger but a good solid FINGER PRESS FIT, sand the socket, epoxy in the new socket in the correct rotation and in-out alignment, and connect existing wires, and add one wire for each turn signal, and solder on the original BMW socket grounding tab.

This is exactly how it is done for the REAR turn signal housings that are on most airheads, said housings typically are on a round metal stalk tube:

Remove the BMW bulb holder (this is the reflector assembly) grounding contact in the turn signal unit; and, ream the plastic center hole for a fairly tight finger-push fit...to about 0.650 inch diameter...it will be necessary to snip off the little original plastic tab that kept the original bulb from going deeper than a certain point (a few reflectors do not have that). DO measure and hand fit, YOUR NEW SOCKET, to the BMW reflector. YOUR socket may not be exactly the same as mine was. A common hand reamer works fine here on the plastic reflector, from both sides, a tad at a time. You COULD use a round file, but please keep the hole nice, and ROUND, and the less taper the better. The socket should be a medium push fit before epoxy work (DO NOT epoxy yet).

I modified the sockets I purchased. They had a 0.350 inch diameter, 1/4 inch long tube area at the rear of the socket, a sort of 'stepped-down' area. You can easily remove the contact/wire unit through the front of the purchased socket. I ground off that rear tube section to JUST FLUSH and then cleaned up (IMPORTANT!) any sharp edges on the center hole where the wires pass through. ....NOTE: There are several types of these sockets, be sure the one's you get have the offset pins. SOME sockets are made such that just grinding off the rear tube area is not quite enough.

Install the 1157(2157) lamp into the socket that already has the wire, insulating washer, and spring. Pay attention to the wires as they exist the rear hole. If any chance those wires can contact the socket metal, then ream out the rear hole and clean it up. Do NOT ream so far that the spring will fall through. You can ALSO add a very SHORT piece of heat-shrink tubing (too long and it is crushed upon assembly to the bike) to each wire at its socket pin, shrinking it in place...and giving added insurance that the pin can not short to the case. Remember, this conversion may be on the motorcycle for decades....we want NO chance of short circuits! Once you have things properly done, and cleaned up, proceed:

Remove the wires, spring, and insulating washer that has the two wire holes in it, from the socket. Clean up the outer surface of the socket with very fine grit sandpaper...for good epoxy adhesion. Temporarily install the lamp, install the socket to the exact correct depth and orientation of thinner filament. Don't push too hard on the glass....remove the lamp after deciding on orientation. Double check this work, and be SURE that you have not mixed up the left and right reflector socket assemblies...so when actually installed in the bike, the thin filament is on top. Be sure the lamp does NOT touch the plastic outer cover lens...and at the same time, the wires are not crushed at the inside. DO NOT epoxy yet!

Now.. you'll be soldering to it: The original BMW brown (grounding) wire will continue to connect to the original grounding clip...which removed clip is now replaced, and SOLDERED to the bulb holder, after first carefully bending its long bulb contacting tab the other way (180 degrees)(don't bend the wrong part). That tab touches the socket in that sanded area, for soldering. BE SURE you do a really clean, well-soldered job here, and snip off any excess of that tab length. You won't be able to solder this adequately unless the parts are very clean and finely sanded and you should use a rosin core solder and a fairly hot iron. Done quickly, no reflector plastic in the slightest will melt. You can NOT do this part of the job UNTIL the socket is installed the correct way for depth and round direction. You do that by making test-tries...that is...test installing the socket, and its rear wires loose behind, and installing it with the 1157 (2157) lamp. The idea here is to NOT let the lamp touch the inside of the outer cover lens plastic material (that means your added red plastic material if you use it) and at the same time not have the socket so deep in the reflector that its rear wires get crushed. Spend a few minutes doing this right. If your items allow, use extra clearance behind the socket for the wires...just so long as the bulb will not come too close to the inside of the still yellow colored outer lense. You will have to put the reflector-socket-lamp assembly into the housing, and then hold the cover onto it....to see the distances of the lamp to the cover.

NOTE: Some reflector units have been seen in which a riveted contact/spade is used. Drill it out carefully, and modify slightly as required.

NOTE: your lamp may have a 'top' mark on it, if so, follow that as far as rotation of the lamp socket is concerned. When the area marked top is on top, you should see the thinner filament is on top, horizontally.

**NOTE: The right side lens fits with the lettering proper (top marked)...but the same lamp assembly part is used by BMW on the left side... installed upside down...as it fits only one way. This means that if you REALLY want to do things 100%...you orient the left side bulb filament and socket at 180 degrees to the right one...ending up so that both sides are the same regarding the BULB orientation, that is, thin filament on top and horizontal. Frankly, bulb orientation is NOT all that important...and, I HAVE seen variations on this stuff: Special NOTE: BMW has made these housings and outer covers in more than one way, and they all look the same at first glance. The inner reflector unit only goes into the housing in one direction....keep that in mind when orienting the lamp, socket, and putting the outer cover up against the housing and reflector, when checking such as bulb clearances and socket orientation. The outer covers have been made in two basic styles, and the drain hole area is for the bottom if you have that drain area. Because of this stuff, perhaps you will want to do one side at a time, and not take the chance of mixing things up and finding something does not fit.

****For front or REAR.....check the fit carefully, setting the socket to the correct depth and orientation, BEFORE epoxying that socket!!! You WILL find you can get at least 1/8" clearance from the bulb to the plastic...a bit on the extra side is nice in case of bulb variations in the future.   Be SURE there is enough room at the rear for the wires to bend sideways without being crushed!

With the new socket to the correct depth and orientation for filament, you can now clean the surface with a rag and bit of solvent, maybe use a scrap of sandpaper if need be, and then epoxy the socket with JBWeld Quikset or similar quick setting epoxy, a tiny dab here and there. Do NOT get epoxy into any slots of the socket. You can dab in the reflector area, as well as the rear area. I dab a tiny bit in the reflector area, then turn the unit over, leaving it reflector open side down, and do the rear.   Very little epoxy is required over-all.    Do this neatly and don't get the epoxy where it is not wanted! BE SURE the depth and orientation is correct, and also correct for the particular left or right bike housing long before you apply epoxy or do soldering!

For the REAR, you should (unless using a paint or lacquer or other coating, as described, on the REAR INSIDE portion of the plastic lens) install some thin flat red plastic material, not cellophane! into the original yellow lens (some paints may be OK, not on sides of the lens please), and as far INTO the lens as possible, and you need to file or otherwise shape the size of this added piece, if you use it, so its edges can be glued into the lens. Again...you want the socket depth to be such that the plastic cover fits, red insert does NOT touch the bulb, yet the socket/wires do not bottom/crush at the rear of the housing. I mostly just paint the inside REAR and don't use plastic inserts.

Connect the original BMW wire in the turn signal housing to the BRIGHTER filament, retest with power ON, to be sure you don't mix them up. Don't leave bare strands of wire here and there. BE NEAT!! NOTE that shrink tubing may well do a better job at keeping the connections small, as opposed to using barrel type of crimp joiners....as there is limited room in the housing.

You will have to add two wires from the running lamp portion of the regular center taillight (or convenient point, depending on model of bike) to the new running lamp filaments....this goes to the LESS bright filament. Run lamp section is green/black on airheads (white-black on airheads with the single dual filament bulbs in the stock taillight, such as a R80ST), inside that taillight. Do this neatly, running the wire through the turn signal mounting tube. Remember that your wiring should be neat, it may have to hold up to vibration for decades. The ST, and some other models are constructed differently regarding the mounting and wiring of the stalks....so, make changes here as needed. It is a NICE touch, if you can, to use the same wire color code for the added wires.

NOTE: If you don't know which is which wire coming from the new socket, then before installing the new sockets, insert the bulb fully and properly, hold the socket outer metal against one terminal of the battery; and, in turn, touch the socket leads, one at a time, to the other battery terminal...and mark the BRIGHTEST lead connection as "turn", mark the dim one as "run".

Be very sure that the wires are not crushed behind the socket! Be SURE the wires are not cut by the end hole of the socket. THIS is extremely important!, and the socket depth before epoxying MUST be checked! YES...I keep mentioning this point. Remember: not too deep to protect the wiring, and not too far out to keep the bulb from touching the plastic. You will have to assemble and disassemble a few times, just to get that correct...a few total minutes. ONCE you epoxy it, it is not going to be moved again!

For the more anal types:
The #1157 bulb (or #2157) as recommended is, on one filament, 12.8 volts at 2.10 ampere rated (this is 26.88 watts), 32mscd light output. That higher powered filament is for turn signal function. The other filament is 14.0 volts at .59 ampere (8.26 watts), 3 mscd. That is the 'running' filament function. This is proper, that 12.8 volt rating, because when the brakes and/or turn signals are in operation, the higher drain pulls down the system voltage a bit, due to little voltage drops here and there; AND, the manufacturer's tend to have the bulb a bit overvoltaged anyway...although this does reduce its life. Don't worry about it all, I am just mentioning it in case you notice a chart of specifications. The original turn signal lamp had the same situation.

The #1176 is NOT an offset pins lamp, and I do NOT recommend you use that lamp or the different part numbered NON-offset socket it requires. In my very first conversion, DECADES ago, I originally used that 1176 lamp, using a mickey-mouse jumper soldered to a lamp contact. Later I once I hand modified the BMW socket to change it to TWO contacts. Again, NOT recommended due to those mickey-mouse things, and the FACT that you WOULD have to identify the bulb contacts as hi and low power, each time, some soldering for every bulb change unless you hand made contacts...well, this is ALL very messy. For those that insist on knowing about the #1176 lamp: 12.8 volts, 1.34 amperes, a lower 21 mscd, and 14.0 volts, .59 amperes, 6 mscd. On a practical basis it is not of much value to know this stuff, just use the #1157 that I recommended (or its equivalent #2157). Use of larger even more higher powered bulbs is NOT recommended.

With the lamp having at least 1/8th inch clearance from bulb to the red lens, there has been no heat related problems on my conversions. Much over 1/8th inch is unlikely to be had with an added red plastic material unless very thin (no problem with painted ones though)...and still keep the wires from being crushed. There have been NO problems without the red lens either...I have done about a twenty of these modifications; some with NO red material added. I know not the legalities of this, but the effect is very nice and neither I, nor anyone else that I know of, has ever been stopped for having constant ON yellow rear lights. I did add red paint or red material to my conversions on my own bikes, and a few others.

If you use a coating, find a red paint of some sort that will stick to the inside of the yellow plastic lens quite well, and thereby not have to install a piece of reddish plastic material. Do NOT paint the inside side walls of the yellow plastic lens.

NOTE regarding the more common of the grounding clip styles removed from the BMW socket:
I bent the forward facing portion that originally contacted the side of the original BMW bulb, rearward, and then reinstalled the clip thing..and soldered it, using a high heat soldering gun...to the cleaned and sandpapered new socket metal. I preferred this to the original pressure contact method...which you could still use, if you wanted to....and, in fact, have found that also adequate....although you will have to do a bit more hand filing....as it requires a slightly flatted area.

Revisions:
05/11/2003: add .htm title
05/14/2003: editing for clarity
06/23-24/2004: modify instructions for bikes using single bulb rear tailight unit; clarify in various places to cover all models, and upload to Internet.
03/23/2006: minor updates...mostly clarifications