I'm totally confused here. I need some help.

[cmyoch]

The minor electrical issues I've had since last fall have been easily fixed due to my peers on this forum. I'm hoping you guys can help again because this one has me totally baffled.

I made it about a mile down the road today when I happened to look down and see both my red tail light indicator light and white headlight indicator light glowing brightly. All of the sudden, I'm a sitting duck. My main fuse had blown. Luckily my wife was able to meet up with a new fuse and I managed to get it home. When I got home, my headlight fuse was blown as well. I traced all of my wiring and did not see anything grounded.

Originally, when I would turn on the key, my headlight failure light would light up until the bike started. Since I took off the headlight to trace wires, I turn on the key and my indicator light doesn't light up. In fact, it wont light up when the light is in either. Also, when I turn on the key and turn on the headlight switch, my tail light failure light glows. It turns off when I flip on the high beam. I have not changed around any wiring whatsoever. Could my regulator have caused the main fuse to blow causing another issue? I'll answer your questions to try to chase down the problem. I missed a good day of riding. Thank god I wasn't miles from home!

 

[TeeCat]

I had this happen to me too, fortunately only about a mile or so from home. These bikes become amazingly heavy when you are pushing them.

I replaced my regulator and rectifier with a combo solid state unit, thinking that might have been it, but it wasn't. (Still, I'm glad I did that.) In my case, though, I had happened to notice that the grommets in my headlight bucket, where the harness goes through, were missing! On the chance that they may have been that way for a while - long enough to rub/crack insulation and cause a short - I replaced them. Ever since then, I have been unable to reproduce the problem, and feel that that cannot have been coincidence.

You mentioned that you traced your wiring, but I just thought I'd suggest this because, to me at the time, it was not obvious. Maybe you'll find something like that to be the culprit.

TC

 

[retiredgentleman]

cmyoch;

You have a short circuit in the headlight circuit. Unfortunately the headlight circuit is a little complicated in the 78 Special.

The wiring goes through or powers many devices...............safety relay, reserve lighting device, hi/low dimmer switch, Lights switch, meter lights and headlight itself.


You will have to use the process of elimination. Start with some of the most likely items to cause a short. Unplug the headlight and try a test ride. If it still blows headlight fuse, try removing or unplugging the meter lights for the tach and speedo. If it still blows, check the other devices one by one.

 

[cmyoch]

TC: That was the very first thing that I checked. I had to get into the bucket a while back to work on a blinker issue and both grommets had been popped out. I have them secured but checked for any frayed wiring anyways. No dice.

RG: I started with the process of elimination. I plugged the headlight back in and was holding it in my hand when I flipped on the switch. I heard a buzzing coming from the light on low and it quit on high. I ran test wires direct to the lamp from the battery and discovered that my low beam was out. SO, my assumption is that maybe the filament had shorted causing the main to blow? Hopefully a replacement lamp will solve the problem and it didn't cause anything else to short out.

One thing that's perplexing though is that my headlight and tail light failure lights must be swapped. I blew a tail bulb a month ago and the headlight failure indicator was lit. Today the tail indicator was lit because of the headlight issue. If that's the case, I can live with that. BUT, I had both lit when I shot craps on the road so I'm hoping something else didn't short with it. Up until today, my headlight failure indicator would be lit when I hit the key and would shut off when the bike was running. Now it's not doing it. I'll replace the bulb and take a test ride and see.

Stand by for an update later!

 

[retiredgentleman]

Yes, sounds like someone has reversed the wiring for the headlight failure and the tail light failure. A little detective work and you can find where they did that.

 

[cmyoch]

Since I'm now on the hunt for a head light, do you have any suggestions? Should I order a specific light from Mikes or is there a good alternative from the auto parts store?

 

[retiredgentleman]

I use a Sylvania H6024 Halogen, 40/60 watt. Bought it at Wal-mart. Works great, but then again I don't ride at night.

 

[Classic]

Same thing happened to me. My high beam filament blows the main fuse... I still havent gotten around to getting a new bulb. The low beam is quite bright and I prefer riding at night.

 

[cmyoch]

Walmart? Thats good because I don't want to have to wait a week or so to get it from Mikes nor want to pay handling charges from 650 Central.

 

[cmyoch]

I went into the local O'Rielly's auto parts store for a blade fuse box and went ahead and picked up a Sylvania H6024 head light for $10. Turns out O'Reilly's warranties them for a year which is great if I blow a couple lights while trying to solve the problem.

I came home and hooked it up. No blown fuses. My neutral light is not glowing though. Is the neutral light and brake failure light tied in together somehow? I'm wondering since neither one is working. I'm going to consult Jayel's wiring diagram and do some more wire chasing.

 

[cmyoch]

After consulting Jayel's diagram, it looks like I now need to be chasing all the brown wires. Looks as if the neutral indicator light and the brake failure light are tied together. Unfortunately, they are tied into the horn, regulator, brake switches, and light checker. As of now, I'm wondering if maybe my regulator failed and caused the initial short. Remember, I blew a main fuse and I can't remember now if the headlight fuse was blown with it. I'll research how to test the regulator.

 

[cmyoch]

Okay so the replacement head light is installed as well as a brand new fuse block with blade fuses. Lights work, signals work, neutral light is on. The only thing that's not lighting up is the light failure indicator when the key is first turned on. I also gave her a couple of kicks to see if the head light turned on automatically, nothing. Does this have anything to do with the RLU? I'm at a loss on how to track this one down!

 

[retiredgentleman]

cmyoch;

You said the "light failure" is not lighting when the key is turned on..............I believe you are talking about the Tail/Brake Light failure, (Red)

The Light Checker has 7 wires at its connector behind the battery. You should use your VOM or DVM to test at the connector. Turn the key on (engine not running)and test for the following:
Red/white.......12 volts
Brown............12 volts
Blue/Yellow......12 volts
Blue................12 volts
Yellow..............0 volts


Black/Red.........ground
Black...............ground
Confirm Black/Red and Black are at ground by putting the positive meter lead on the battery positive.

A couple of kicks is not enough to turn on the headlight. The alternator has to produce enough voltage to operate the Safety Relay coil. If your alternator/charging systems are working then the SR will turn on the headlight.

 

[cmyoch]

I'll run that test. I only kicked it 2 times so maybe several more kicks will get it to turn on. Since my wiring to my light failure indicators appear to be backwards, it is my headlight failure warning light that lights up when I hit the key at startup. I'll need to tinker around and fix that someday.

 

[cmyoch]

Ok. I have 12v at all but the blue wire. I tested with both the headlight on and off. I also get 5v out of the black/red wire before testing ground. Is something wrong or am I overlooking something here?

 

[cmyoch]

Well I kicked it multiple times and no lights. I'm wondering if that unit is shot. If so, is there a bypass somehow?

 

[cmyoch]

Okay. I got the bike started. The head light came on and the tail light failure indicator lit up except it didn't turn off after the bike remained running. I checked the tail bulb and it is perfectly fine. Time to consult the wiring diagram again!

 

[retiredgentleman]

You're reading the wrong voltages on the blue and the yellow wires. If you are seeing 12 volts on the yellow wire, that means the brake light is on. Have you checked that the front and rear brakes actually turn the brake light on and off ?? One of the 2 brake switches may be mis-adjusted causing the brake light to be on at all times. You need to correct this problem first.

The blue wire should have 12 volts to supply the tail light, but you say it has 0 volts. Well, sort out the brake light problem first, and that may make things clearer.

 

[cmyoch]

I have noticed that the return spring on the handlebar is weak which causes the lever to keep enough pressure on the front switch to activate the brake light. I will run a new test on this as well as the regulator tomorrow morning.

 

[cmyoch]

I tested again and I get the same results from the plug. I also tested the battery past 3,000 rpm and I cannot get more than 12v. I put brand new brushes in the other day. I'll pull them again and test the resistance between the rings.