Topic: Question for the electrical geniuses on here

[jakec]

I'm trying to figure out my brake light. Bike is non stock but I am using a brand new OEM switch and wiring per the manual. The problem is that the "running" filament doesn't come on.

I'm using a two-filament OEM blinker unit as a brake light (left). The brake light that came on the bike is shown on the right. The one on the right works just fine. They both have a seemingly identical setup. They both have a ground wire that hangs off, which is not needed by either. As they both mount directly to the sissy bar and ground that way. I have tried using alligator clips to ground the desired housing to various points on the bike but no success.

[Gurp]

Unplug at the first point past your brake light switch and test it there.
 If it works there could be a bad connection with the one not working.
If it works figure out the bad connection.
If it doesn't (likely) take a mulitmeter and see if you're getting voltage or just a voltage drop.
If it's a used assembly may be old solder connections breaking.

[jakec]

One wire is direct from ignition to the brake light. One is ignition to the brake light, with the switch in the middle. Since it is simplified wiring no other connections inline.

Don't I want to test the wire/socket connection that is for the wire that isn't on the switch? As the switched filament is working.

One thing I forgot to mention, the big brake light on the right, if I hold it in my hand it works just like the one on the left. But if I hold it up to the sissy bar and ground it, it works. However the same trick doesn't work with the unit on the left.

[bryanj]

Thats because on the blinker the socket is rubber mounted and need the ground wire, you will see one end on a mounting screw, the other is soldered to the bulb socket and frequently falls off

[Deltarider]

I'm trying to figure out my brake light. Bike is non stock but I am using a brand new OEM switch and wiring per the manual. The problem is that the "running" filament doesn't come on.

I'm using a two-filament OEM blinker unit as a brake light (left). The brake light that came on the bike is shown on the right. The one on the right works just fine. They both have a seemingly identical setup. They both have a ground wire that hangs off, which is not needed by either. As they both mount directly to the sissy bar and ground that way. I have tried using alligator clips to ground the desired housing to various points on the bike but no success.

Maybe it is just me, but I don't get what you're talking about. The brake light is the same as the taillight. There is supposed to be a dual fitting socket in it. It needs a dual filament bulb. As far as 'running lights', these bikes had them only in the front blinkers, not in the rear. What is it you want?

[drumstyx]

If I understand you correctly, you're trying to use an OEM front blinker as a tail/brake light, yeah?

Start simple: pull out the multimeter and make sure you've got continuity between each wire end and its corresponding contact in the socket. Make sure you've got voltage at each connector on the harness when appropriate, and then lastly, check the socket connected directly to 12v (battery or otherwise) with a bulb in it. Could just be that things aren't lining up correctly in there.

[jakec]

Thats because on the blinker the socket is rubber mounted and need the ground wire, you will see one end on a mounting screw, the other is soldered to the bulb socket and frequently falls off

The ground wire you're referring to is visible in the photo right?

[jakec]

Maybe it is just me, but I don't get what you're talking about. The brake light is the same as the taillight. There is supposed to be a dual fitting socket in it. It needs a dual filament bulb. As far as 'running lights', these bikes had them only in the front blinkers, not in the rear. What is it you want?

Sorry for the confusion but I am using the running light (round OEM unit) as my brake light. It does have a dual filament socket inside and I am using a dual filament bulb.

[jakec]

If I understand you correctly, you're trying to use an OEM front blinker as a tail/brake light, yeah?

Start simple: pull out the multimeter and make sure you've got continuity between each wire end and its corresponding contact in the socket. Make sure you've got voltage at each connector on the harness when appropriate, and then lastly, check the socket connected directly to 12v (battery or otherwise) with a bulb in it. Could just be that things aren't lining up correctly in there.

Great ideas, thank you.

[BenelliSEI]

Jake...  connect the tail light to your bike. First, clip your test light to the POS terminal on your battery. Anywhere you touch on the bike should provide a ground, so the test light should light. Does it light up when you touch your taillight? Now touch the actual lamp socket, still lights up? If “yes” to both, your lamp is properly grounded.

Step 2. Connect the test light to the NEG terminal of your battery (or a convenient ground nearer the tail light). First check the two leads to the tail light. One should have power when you turn on the lights, the other should power up when you apply the brakes. If both leads light up the test lamp. Your problem is in the socket itself.

Step 3. Connect the wires to the two leads to the tail light(bulb removed). When you turn on the lights, one of the small lamp base contacts should be live. Careful poking your test light in there, remember the outer case is the ground. If you touch the contact and the base, you will cause a short and blow the lamp fuse. Now apply the brakes. The other contact should come alive?

Take NOTE: if it all works with the above tests, the problem is the bulb. The two contacts on the bulb, must line up exactly with the contacts in the base of the socket. Do they?

[BenelliSEI]

Jake..... this kind of Test Light. Cheapest, most useful.

[jakec]

Ok I have not tried all of the tests above yet (need some time). But I do have one other piece info. With the small OEM light installed, using the brake makes 1/2 filaments light up. If I switch the wires, both filaments light up all the time, and the brake switch does nothing. I guess what this tells me is that both connections on the bulb are being made just fine.

I also have the brake light power wired directly to the ignition and it is not dependent on the headlight being on.

[jakec]

I also confirmed that it’s grounding by removing it (doesn’t work) then connecting with and alligator clip to the same spot on the bike (works again).

[jakec]

So I considered the comment here about the contacts a little more and when I removed the bulb I noticed it was really difficult.. so I finally got it out and the contacts looked dirty. Tried to clean them but installing the bulb was still difficult. Finally tried with another identical unit (got my hands on a set of 2) and the other worked. So I believe it was just socket/contacts being bad.

[drumstyx]

Ok I have not tried all of the tests above yet (need some time). But I do have one other piece info. With the small OEM light installed, using the brake makes 1/2 filaments light up. If I switch the wires, both filaments light up all the time, and the brake switch does nothing. I guess what this tells me is that both connections on the bulb are being made just fine.

I also have the brake light power wired directly to the ignition and it is not dependent on the headlight being on.

Are you sure it's both, and not just the brighter filament coming on when you switch it? Test that you have 12V at the connector for running (tail) light, and then connect that to each filament connector. If one works, and one doesn't, it's 100% a socket issue (wiring at the contact maybe) or bulb not fitted right. You can usually pull those sockets apart and replace the contacts if you need.

You really ought to have a multimeter for this testing, and it's absolutely worth the $5-15 you'll pay, assuming you don't already have one. Testing the socket is as easy as testing continuity between the contacts inside and the bullet connector on the wire.

Another thing would be to make sure the contacts are aligned identically to the old one relative to the locking lugs.

[BenelliSEI]

So I considered the comment here about the contacts a little more and when I removed the bulb I noticed it was really difficult.. so I finally got it out and the contacts looked dirty. Tried to clean them but installing the bulb was still difficult. Finally tried with another identical unit (got my hands on a set of 2) and the other worked. So I believe it was just socket/contacts being bad.

If your other lamp works fine, the fibre plate inside your first socket has rotated. The pins are not aligning with the bulb. Compare them and you will see the difference......

[jakec]

I believe that you guys are correct and the alignment may have been bad, and the contact lighting up when the wires were switched was actually the brighter filament, not both.

I do have a volt meter with multiple settings.. but I am not sure if it's a multi meter.

[BenelliSEI]

If it has multiple setting (Ohms for resistance and DC/ AC volts) it’s a multi meter.