Author Topic: New Tail Light then dead battery? (Read 1324 times)

mjc425 · « **on:** April 25, 2011, 02:51:28 PM »

I just hooked up a new tail light to my 72 CB500 this evening and after testing it twice it seems like my battery died.

The tail light has three wires (red, yellow, black) and is not LED. Before mounting it to the fender I hooked up all the wires, turned the key and squeezed the brake a few times. It worked. So I mounted it, wired it up again and then turned the key and squeezed the brake again. It turned red for a second, but when I pulled the brake it went out and then nothing worked (headlight, horn, starter).

I tried unhooking the wires to just try the horn again and still nothing. So I pulled the batter and it's dead.
I'm charging it, but before I throw it back on there any ideas as to why this happened and how I can stop it from happening again.

ekpent · « **Reply #1 on:** April 25, 2011, 03:14:18 PM »

How old is it,may just be a coincidence.

mjc425 · « **Reply #2 on:** April 25, 2011, 04:02:17 PM »

The tail light is brand new, but I'm not 100% about the battery.
When I was first trying to get the bike running a few months back it took quite a while took drain the battery while continually pressing the starter.
Could be that it's time for a new one, but I'm hoping that it just needs a good charge and that I did something dumb while wiring the light.

SanDogDewey · « **Reply #3 on:** April 25, 2011, 04:09:47 PM »

Is it a stock taillight? If not, is it drawing more amps than a stock one? Is it possible you blew the fuse when you had the brake on?

mjc425 · « **Reply #4 on:** April 25, 2011, 04:50:34 PM »

It's not stock and it doesn't have any info on the packaging.
Maybe it says on what the amps are on the actual light somewhere?
How may amps is too many for the this bike?

oh- and if I did blow a fuse how do I go about getting a replacement and then replacing it. I've done this a lot on my jeep, but not sure about motorcycles.

phil71 · « **Reply #5 on:** April 25, 2011, 04:56:58 PM »

in 72, you can take the key out in 2 positions out of 3. one will leave the parking lamp on. SUper unlikely, but a thought.

mjc425 · « **Reply #6 on:** April 25, 2011, 06:31:06 PM »

So I just put the battery back in and nothing. The charge was at 100% and I didn't have anything wire hooked up in the tail light.
I figure it must be a fuse now and that the light is just too much for the battery.

patman · « **Reply #7 on:** April 25, 2011, 06:40:06 PM »

always go back to where you started check all your grounds and for pinched wires

edbikerii · « **Reply #8 on:** April 25, 2011, 06:46:00 PM »

I bought brand-new lockhart-phillips turn signals once. They worked great in the garage, and for a about 20 minutes on the road. Then one of the bulbs shorted out INTERNALLY. Yes, strange. Blew the main fuse. Took me about 30 minutes to finally track that one down on the side of the road, cursing.

mjc425 · « **Reply #9 on:** April 25, 2011, 07:02:14 PM »

I'm pretty sure that it has to be the fuse. With the battery fully charged it should at least be giving power to the headlight or dummy lights.

So as someone not familiar with bikes or something this old.... where is the fuse(s)? I've been searching the forum all over and checking my clymer with no real good leads.
Pics would be awesome and also a tip on where I can get a replacement.

SanDogDewey · « **Reply #10 on:** April 25, 2011, 07:50:21 PM »

Quote from: mjc425 on April 25, 2011, 06:31:06 PM

So I just put the battery back in and nothing. The charge was at 100% and I didn't have anything wire hooked up in the tail light.
I figure it must be a fuse now and that the light is just too much for the battery.

The light is too much for the electrical circuit. The light must be pulling quite a few amps to only light the light a couple of times. Not sure where the fuses are on a 72 CB500. On my 77 CB750 and 75 CB400F they were under the left side cover. Time to find a stock light or one that draws less amps.

DarcyCB400F · « **Reply #11 on:** April 25, 2011, 07:59:20 PM »

What is the bulb number?
Some use the wrong bulb...

Check and replace the fuse if neccesary and report back with the bulb info.

After you recharged your battery, did you get anything to work like headlight, horn or guage lights? Does it start and run?

mjc425 · « **Reply #12 on:** April 26, 2011, 12:46:35 PM »

As requested Darcy-
Is the fuse the small glass cylinder with two silver ends?
If so the metal bit inside looks like it melted or something in the middle. I'm used to my jeep fuses, but I'm guessing this is same thing and it needs replaced.
The fuse I have says 20 on it. Is this what I need? Can I get a replacement at any auto place?

The bulb number on the new tail light is 12V23/8W
I have the stock bulb. Can't read it and it's too big to fit in there.

Thanks for all the input everyone. Today's the first day without rain in about 2 weeks and I really wish I was out there.

DarcyCB400F · « **Reply #13 on:** April 26, 2011, 08:01:35 PM »

Quote from: mjc425 on April 26, 2011, 12:46:35 PM

As requested Darcy-
Is the fuse the small glass cylinder with two silver ends?

If so the metal bit inside looks like it melted or something in the middle. I'm used to my jeep fuses, but I'm guessing this is same thing and it needs replaced.
The fuse I have says 20 on it. Is this what I need? Can I get a replacement at any auto place? The bulb number on the new tail light is 12V23/8W
I have the stock bulb. Can't read it and it's too big to fit in there.

Thanks for all the input everyone. Today's the first day without rain in about 2 weeks and I really wish I was out there.

Yes the fuse is the glass tube with the siver ends! Good find! Any auto parts store will have replacements for sure. Be sure not to repalce the fuse with a higher rating than in specified for your bike. It has "blown" because the power in the circut has found "ground" this is not good... you need to find where it has "shorted out" and repair or you will continue to "short out".

The bulb will have another number on it like, 1073, 1157 or some such number...

Can you take and post some pictures?

SanDogDewey · « **Reply #14 on:** April 27, 2011, 07:27:22 AM »

The stock 1157 bulb is rated at 2.1 amps for the brake light and .59 amps for the tail light.

TwoTired · « **Reply #15 on:** April 27, 2011, 09:26:40 AM »

Quote from: SanDogDewey on April 27, 2011, 07:27:22 AM

The stock 1157 bulb is rated at 2.1 amps for the brake light and .59 amps for the tail light.

Point of clarification:
The earlier SOHC4s used 1034 bulbs in the tail light. These were rated 1.8A / 0.6481.8 / 0.648 @ 12.8 V
http://www.donsbulbs.com/cgi-bin/r/b.pl/1034.html

Later models did use the 1157 in the tail position only. But, I'm not sure the year of changeover.

Cheers,

mjc425 · « **Reply #16 on:** April 27, 2011, 03:39:28 PM »

I replaced the fuse and nada- it didn't blow again. Just NOTHING happened....
no horn, light, starter, etc... but no blow.
I'm going to put the stock light back on and then try things.

What if this doesn't work? Worst case scenario could I have really shorted out some major electronics?
I should have never strayed from stock...

TwoTired · « **Reply #17 on:** April 27, 2011, 04:01:06 PM »

Quote from: mjc425 on April 27, 2011, 03:39:28 PM

I should have never strayed from stock...

What? You'd rather ride than work on the bike?

On the frontier, you could identify the pioneers by the arrows sticking out of their backs.

Cheers,

mjc425 · « **Reply #18 on:** April 27, 2011, 06:58:56 PM »

Road ready again!
Wired up the stock tail light and re-charged the battery and vavoom...
Now I just have to re-mount the light and remember that stock is alright with me.

Thanks for any and all advice. This forum continues to be the go to place for all problems.

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Author Topic: New Tail Light then dead battery? (Read 1324 times)