LED tail lights, grounds .... Maybe not THE problem, but found A problem ...

[normzone]

You know, this stuff would probably be easier if I wasn't developing some serious tooth pain - I've adjusted my chemical balance and am mentally inventorying the odds and ends of pain medication in the cupboard, and wondering about my weekend.

But that's not why we're here today. We're here because I thought I would be clever and change my tail light bulb to a red LED.

Or maybe not - anyway, that's when I first noticed my lighting was acting weird.

I dropped into the red led thread and got some help, which I have copy/pasted below: (cue flashback)



[Normzone]

My local Oh Really? had the [Sylvania LED, Red P/N 2357R. Comes in a pack of two for 20 bucks.]

So I put it in the Bassa, and when I did I got no brake light just tail. Checked out the original bulb, all good.

Tried the LED again, all good, chalked it up to user error or aged contacts.

This thread just made me go check the brake light so I could have something nice to think about, and .... no brake light. Again.

a) I'm nuts - could be
b) Some heretofore unidentified system incompatibility 'twixt my bike and that bulb
c) aged contacts



[Tom]

Check the contact tabs in the socket to make sure they're not pushed down too far.



[Normzone]

Thanks [Tom].

I just took it apart

played with it
cleaned the contact areas
checked with the new LED
checked with the old 1157 bulb
checked with a new 1157 bulb

and the answer is simple - I've got no brakelight. Neither front lever nor foot pedal will activate it.



[Kiwi_Roy]

Assuming it's the Bassa from your profile.

http://www.thisoldtractor.com/guzzi007/schematics/2000_Bassa.gif

Is the headlight On?  (Headlight Relay (22) energized)

For some weird reason the brake lights are supplied through the headlight relay on those California models
I guess Guzzi needed every last milliamp for the starter.



[Normzone]

Hmm...

Didn't check the headlight, but damnit, I'm about to turn this into ANOTHER [normzone] has electrical weirdness thread.

Just came back from trying both LED and standard filament 1157 in the tail/brakelight socket.

It all works good when turn signals are off, or when right turn signal is on. Bulb type does not matter.

When the left turn signal is on, the license plate light and the tail light flash a few times in synch, then stop. No brake light or tail light function after that.

I pulled all the relays (stock Siemens, five pin), sneered at them and put them back. I'll order replacements tonight. (Update: Replacements have been ordered - he graciously got them on the way to me while out the door on his way to the IL rally)

I pulled all the fuses, and the low amp blue ones (5?) (15?) all look good, but the yellow (20?) one looks the worse for wear.

Is my turn signal switch shorting out?



[Kiwi_Roy]

No you have a missing ground, the tail and LH rear signal are floating.

The tail light current is passing thru the left rear and left front signal lamp in series.

Ground the tail light and LH rear signal lamp properly and all will return to normal.

This is quite a common fault.

Update
http://www.thisoldtractor.com/guzzi007/schematics/2000_Bassa.gif

The schematic shows the tail light grounding in surprising detail, of course the beautiful art deco fitting is not made of conductive metal but non-conductive plastic.

You may find the fault is not in the tail light at all but at the point where wire (2) is grounded, good luck finding that. It wouldn't hurt to run an extra ground.

The stuff that keeps me awake at night



[Normzone]

All was well until I changed the brake / tail light bulb. I wonder if there was a ground there that I disturbed then and did not reattach when I put the assembly back together - two screws and two spacers. I guess it's time for a look - I'm getting pretty good at removing those two screws and putting them back in - it's well within my technical capability, even if they are phillips head.


(end flashback)


So, with a sore jaw and a good buzz on, I go verify my findings.

[Kiwi_Roy] seems to have a point - the low beam on my headlight is non-funk - I only have the high beam. Tested it with a new bulb, same story.

I pulled all the relays and swapped them around - nothing changed.

I swapped all the 15 amp fuses, and sneered at the yellow (20?) amp. No changes.

I looked at the Bassa wiring diagram. Is that black wire, there and in my taillight assembly, the ground? Whatever happened to green means ground (my first Honda)?

I don't see anything in the way of a misplaced ground connection in the brake light shell.

And yes, when I put on the left turn signal, the tail light and license plate light pulse in harmony.

That's all I got. Well, that and a buzz .....

[Zoom Zoom]

Did you ever pick up a volt/ohm meter?

If not, they are very inexpensive these days. Something everybody ought to have for sanity sake.

Begin with bike not running, key off.
Set the meter to volts. Something just over 12 volts DC (VDC) is what you want. With one probe to ground, meter each wire for voltage. If, (and I doubt you would), take note of any wire you find voltage on. Now switch the meter to ohms. EXCLUDING any lead you discovered voltage on, meter the wires to ground. 0(zero) ohms is good continuity to ground. It may not be 0, but a very low number like 10 ohms or whatever. 2K(2000) ohms would be a very poor ground for example.

Now turn on the key and retest all the wires. Again taking note which has 12 VDC on them. Get someone to press the brake pedal and handle and verify voltage on the wire that supplies the brake light.

HINT: The wire in the brake light assembly that is the ground should be the one that makes contact with the side of the bulb.

Bike does not need to be running. When all is said and done, you should find two wires to each bulb that will either have voltage on them or have voltage when a brake lever is activated. You should have one wire to each bulb that is the path to ground.

**Do not set the meter to ohms and meter a "hot" wire.** That is why you begin by ruling out the supply wires.

Now, if you did not find voltage on two wires, you will need to locate why. If you do not have a path to ground with the third wire, you need to locate that trouble.

So far, we're only dealing with the tail lights here. Same process would be used for trouble shooting the headlight. Of course the high beam switch will energize the other wire.

Back to the tail lights. It is not uncommon on bikes like yours to have a wire rubbed through under the rear fender. there is a small round connector under the seat with three pins in it. You will see it just ahead of where the wire comes out of the fender in a rubber grommet. You can unplug that and meter that wire, (each conductor), end to end. If it has rubbed through underneath, you will need to do a proper repair. (I myself would solder in and shrink wrap the wire, then re-wrap the harness with electrical tape.)

Now it could be a bit more complicated depending on how the switch is located in the circuit, but I'll not confuse you with that since I don't believe it applies here.

Take some meter readings and report back here if in doubt.

John Henry

[93spada]

Hi Folks
Sounds like the circuit goes thru a relay?
Look for and change it out to an LED compatible??
Fixed my winkers with a bit of fiddling.
Paul

[swooshdave]

I looked at the Bassa wiring diagram. Is that black wire, there and in my taillight assembly, the ground? Whatever happened to green means ground (my first Honda)?

Black is typically ground on most bikes.

[normzone]

Well .... my tooth is still giving me what for intermittently, but I'm undrugged at the moment.

I followed the instructions laid out by [Zoom zoom] (John Henry] after looking for broken wires at both ends of the bike [Kiwi_Roy].

" Begin with bike not running, key off.
Set the meter to volts. Something just over 12 volts DC (VDC) is what you want. With one probe to ground, meter each wire for voltage. If, (and I doubt you would), take note of any wire you find voltage on. "

>>>>Yup, no juice to any wire with the key off<<<<<

Now switch the meter to ohms. EXCLUDING any lead you discovered voltage on, meter the wires to ground. 0(zero) ohms is good continuity to ground. It may not be 0, but a very low number like 10 ohms or whatever. 2K(2000) ohms would be a very poor ground for example.

>>>>Zero ohms or close, still no hot wires<<<<<

Now turn on the key and retest all the wires. Again taking note which has 12 VDC on them. Get someone to press the brake pedal and handle and verify voltage on the wire that supplies the brake light.

>>>>> Tail light gets just under 12V on the right side - left side gets about the same when brake pedal depressed (as am I now) <<<<<

HINT: The wire in the brake light assembly that is the ground should be the one that makes contact with the side of the bulb.

Bike does not need to be running. When all is said and done, you should find two wires to each bulb that will either have voltage on them or have voltage when a brake lever is activated. You should have one wire to each bulb that is the path to ground.

So after dinking around a while I looked for the " small round connector under the seat with three pins in it. You will see it just ahead of where the wire comes out of the fender in a rubber grommet. You can unplug that and meter that wire, (each conductor), end to end. "

Mine is different. It comes out by the battery as two sealed connectors, similar to the now-removed side stand switch wire. CUTE little connectors. I figured out the black wire in one of the set would be ground to the rear, and verified it had zero ohms resistance.

So I figured, if this mess WAS a ground wire fail, then a ground wire from the (ground wire of the) taillight to the negative terminal on the battery should change conditions for the better. Well, the parking light got a little brighter, the problem persisted, and now the left turn signal does not function.

I had a friend with a pre-unit 1957 Triumph who's wiring was about three wires all told. I wonder ....   

[normzone]

I was wondering if my changing that tail light bulb was not the cause of the issue, but only the method by which I noticed that there was a problem.

Inventorying unlikely events that may have been part of the influence leading up to this, I can only think of two.

1) I changed out the stock horns for Hella. I noted that they worked in either connector configuration.

2) My speedo gave up it's final function - the needle now flops around like a stick on a string. The odometer went first, followed by the trip meter.

Since I do virtually no night riding, there's been no opportunity to note that the low beam was not getting power. And the front running lights are wired into that hot lead, so they're no longer in the game either.

Still runs though. But I'm afraid to ride it until I understand what the #@&& is going on.

[Kiwi Dave]

Black is typically ground on most bikes.

Moto Guzzi changed to blue for ground in 2005 I believe.

[Kiwi_Roy]

For sure you have a bad ground to one or all of the lights in the tail area.

Take a 6 ft wire and connect one end to a gearbox bolt, touch the other end to the brass contact of the various bulbs which you see malfunctioning this will supply a good ground to replace the one that's missing.

[normzone]

Alright ....

We're back at it again. First thing, I put on the new head guards, so I could feel like I accomplished something.

Then I hooked up a ground wire to the head guard, verified it was grounded with a light bulb to the battery.

Then I turned on the key and tried it against the ground connector on the side of the tail light assembly. I got some sparking, which means that there is power leaking to that ground?

And I also learned that the hand brake lever brake light switch sticks sometimes.

Going out with pen & paper to write down all the symptoms so I don't forget anything.

My fevered imagination is leaning towards shorted brake light socket or turn signal switch.

[normzone]

Feel as though I'm creating the medical chart hanging at the foot of the bed - Oh, that's probably all called up on a tablet now ...

Status:

Key off:

all grounds show zero ohms resistance
no volts to any point at the brake / tail / turn signals

Key on:

no lo beam on the headlight
when hi beam and right turn signal turned on, fast pulsing RIGHT front turn signal after momentary pause, hi beam is on steady
when hi beam and left turn signal turned on, fast pulsing LEFT front turn signal after momentary pause, AND hi beam pulses as well


 Key on, signals off:

right side tab connector to tail light socket 12V

left side tab connector to tail light socket 0.14V

tail light ground wires off side of socket/bulb also 0.14V

Key on, signals on:

right side tail turn signal socket shows changing volts, 5 - 8 - 5 - 8 .... bulb flashes
left side tail turn signal socket shows steady 3 volts, does not light or flash

[Tom]

Reading the thread is driving me crazy.    Sorry to hear the lack of results.  Just curious.  Are the LED bulbs good?  Just for the heck of it see if they have continuity or try them on your car.  Just to eliminate them.

[normzone]

Writing it is making me crazy. 

I can swap the regular incandescent & LED tail lights and I get the same results. For my own sanity all testing performed with incandescent.

EDIT: And my tooth is giving me what for again, so I guess I'll be in to the experts next week .... and probably drugged up tomorrow. We'll see if I'm comatose or just amused at thinking very slowly and wiggling wires on the bike.   

[Kiwi_Roy]

A couple of posts back you said you had 10 Ohms to ground, was that on one of the black wires, if so thats through a lamp filament not a direct path to ground.

Did you try the wandering ground lead like I suggested in post No 7?

[normzone]

Hi Roy -

All my ohms are good, that 10 ohms reference was me quoting John Henry/Zoom Zoom

Yes, but all I've tried touching it to was the ground connection coming out of the tail light - that's when I got a little sparking. It didn't have an effect on the symptoms.

Is that sparking an artifact of completing the ground circuit? My mind interpreted it as evidence of errant power to that ground point, but what the #%% do I know?

I did my dentist a favor a while back and have her phone number,  texted her on this Sunday night and she's called in some antibiotics for my now swollen tooth. She apologized for not being allowed to call in good pain meds, but I told her I can sort that out.

[Zoom Zoom]

It was mentioned that you may be seeking a path to ground through the filament of a bulb. Good catch. For trouble shooting purposes, it would probably be a good idea to remove any bulbs so you could not possibly be finding a path to ground through one of them. I apologize for not mentioning/thinking of this in my other reply.

As for sparking, You found a wire that has voltage on it.

John Henry

 

[Kiwi_Roy]

Yes, as Zoom Zoom says you have Voltage on the ground, the sparking is because the bike ground is bad.
It may be connected to a rusty bolt up around the seat area or perhaps it's cut through, don't even bother trying to fix anything else until you fix that or replace the wire.

Bad grounds can cause all sorts of weird effects and they are probably the most common lighting fault.

Have Fun

 

[normzone]

Today's sullen tinkering yields the datum the the front (hand brake) brake light often sticks on - I wonder if that means disassembly of the handlebar mounted collar containing the associated goodies, or if there is a port in there designed to spray DeOxit through 

[Kiwi Dave]

No need to dismantle, the micro switch is on the outside of the front brake lever.  (Unless you've got something unusual.)

[normzone]

Thanks, [Kiwi Dave]. Yeah, that switch is TINY! It looks pretty well sealed up - I will talk to it and threaten it with a spray can of lubricant, but I don't know if it will be impressed.

I've decided to stop trying to figure out my problem, and just follow some trails for a while.

I figure I'll start with the three grounds that come off the negative terminal and see where they go to, clean those connections.

I'll also start at the low beam and work backwards and see where/why the power to it gets stuck, since it has none.

I sprayed some contact cleaner into the turn signal switch yesterday - you could tell afterwards that there had been grease in there before but that there was none now, but no other changes.

I also tried disconnecting the Hella horns, since that was the most recent electrical modification I made to the bike. That also had no effect.

I'm about ready to put it back together and ride it and see what happens. Who needs turn signals?   

[normzone]

I have updates - no panacea yet, but ....

I made a list of the symptoms and things to check. Some are less likely than others, but I'm already grasping at straws, so why not?

I replaced all turn signal bulbs. They said Italy on them, now they say China. Didn't change the problem. I tested the system with NO turn signal bulbs in ... still weird.

Just to refresh everybody's memory, here's what the weird is .... With the left turn signal switch activated, the front left turn signal bulb is dim and slow. And the rear left turn signal bulb does not light up. AND the tail light filament pulses in time with the turn signal.

I figured out that the front brake light switch was stuck on .... sometimes. No visible grief there, I took it off, sneered at it, put a drop of oil on it and it's associated ball bearing in the lever mount, and it's all good.

I'm now going to work back from the headlight shell (why no low beam power, but high beam works fine?), and I'll take off the tank so my wife can change the air filter (she can't remember that she wanted to do that, but it will be quality time spent together  )

[Tom]

Bike runs but nothing on the turn signals?  Have you checked the handle bar controls?  Corrosion?  Does your bike have the turn signal indicator module that looks like a little cylinder.  Change that?

[normzone]

Hi Tom - Yeah, bike runs fine, if I wasn't worried about the turn signal issue turning into a roadside breakdown I'd just ride it.

But a simple search for loose or shorted wire has become a seat, sidecovers, tank all removed kind of hunt.

My wife just changed the air filter, did a great job. I'm so proud ....

I thought about changing the turn signal flasher unit, but if it works for one side then wouldn't it work just fine for the other? They're not bi-lateral, are they?

AND WHAT THE #$%@ is that little sensor thingy mounted to the right side tank mount? It has a harness going to it, looks like some kind of air temp sensor or good luck charm ...

[Tom]

Change out the flasher unit.  It can fail on one side only. 

[normzone]

I now have a new turn signal flasher. That's okay, it's more cuter than the old one.

Same problems though.

It looks as though headlight low beam power goes through a connector (no power on that wire there either side) and up into the dashboard, and then to the switch on the left handlebar. What happens if I open up that switch box ?

[Tom]

Possible corrosion in there for a bad connection.

[KiwiKev]

Sounds like a bad earth on the tail light if the stop light is coming on. Current is finding its way to ground thru the stop light .

Check your ground connection.


Sent from my iPhone using Tapatalk

[normzone]

It just gets worse.

I figured if I had a floating ground (term for a circuit that lacks a ground, says the google), touching a ground wire to the side of the turn signal (ground point for the bulb) should establish ground, and if that were the sole problem, it would go away, at least while I hold the wire there. So I took the test ground that I'd hooked up to the engine and did so.

And the problem went away - the turn signal worked fine, the brake light worked fine.

And when I took the test ground away, IT KEPT WORKING JUST FINE. AS IF THERE WAS ALWAYS A GOOD GROUND THERE, AND NEVER ANY PROBLEM. Turn the key off, turn it on, same story. No new ground circuit in place, but old ground circuit functioning just fine.

But THAT'S not the bad part.

Remember the lack of low beam power to the headlight, but the high beam worked? WELL NOW NEITHER BEAM IS GETTING ANY POWER. No headlight. No hot wire to it. Nada, nothing, zip, zilch, zero. And all the fuses are good.

Disregard, I left a harness I'd been exploring unplugged. I don't know if it has power now, or not. And I'm beginning to not care.

[normzone]

Oh ho, and now it did it again.

I was looking for a positive stopping point in the day, and I turned on the key, played with brake and turn signals.

It works .... it worked. Brake lights, turn signals, all good. Still no headlight power.

Then, while I was watching it, IT WENT BACK TO IT'S PREVIOUS CONDITION. No turn signal, brake light pulsing instead.

So I thought, if touching a ground wire to the side of the turn signal made it work before, it should do it again, so I did.

AND IT DID NOTHING. No turn signal function, even with a forced ground.

It is insured against fire ....

[oldbike54]

 Have there been any UFO sightings in San Diego recently ?

 Dusty

[normzone]

Well, there was a plane towing a banner early this morning ....