Topic: Motogadget M-unit Troubleshoot (SOLVED!!)

[FridgeRaider]

I'm trying to see if anyone has some advice on a very specific problem I'm having concerning the Motogadget M-unit. I finished restoring a 74 CB750 for my father at the beginning of this year and upgraded the electronics with a custom wiring harness powered by the M-unit. Here's the issue: when the M-unit is turned off by turning the key to off, it leaks power to the headlight. This can be noticed by the faint glow the headlight puts off. If left like this overnight, it will drain the battery completely. We tested it with a multimeter and got about 1 volts of power still running through the headlight. When we first got the bike running, it didnt have this problem. Over the course of 6 months the problem has plagued us by showing up and then fixing itself with only some head scratching involved. Unfortunately now it's back again. My father's current solution is after every ride, he disconnects the negative terminal from the battery. He says that he can reconnect it immediately afterwards and the headlight will stay off until he turns the key and powers the M-unit back up again. Thanks in advance for your time and any advice/suggestions would be appreciated. 

UPDATE: Thanks in great part to Kwaka74, the solution to my issue is actually confusion about a built in feature of the Motogadget M-unit that I was unaware of. The voltage bleed is from using toggle switches and leaving the lights on Hi when turning off the M-unit. This will turn on the parking light function and eventually drain the battery.

For more detailed info about this, read further on!

[SOHC4 Cafe Racer Fan]

Hey Cal, resident M-unit guru, any words of wisdom?

[DaveBarbier]

Did you happen to make a wiring diagram for your new harness? What happens if you connect the tail light or test light to the headlight output (on the right side of the mUnit) and ground it properly? Will it act the same? Can you tell whether it's the low or high beam that stays on? Maybe remove the high or low on the mUnit to determine this?

If it's actually connected properly it sounds like a faulty unit to me.

Cal will most likely chime in with better advice

[540nova]

Warranty time


Sent from my iPhone using Tapatalk

[calj737]

Odd, I happen to be in Orlando today and tomorrow Harrison.... Maybe I can stop by tomorrow on my way to NPR?

[thirstforspeed]

i built a Virago like this and had this exact same problem. leaks voltage to the headlight, but only the main beam, not the high beam. I think its a warranty thing. if someone knows why it does this, pls advise. its weird and i would like to fix it if i could.

here is the bike:


i wired it like they recommended (AFAIK) here is the wiring diagram for it:

[calj737]

Thirsty - your problem is the LIC/Running lights are wired to the M-Unit power terminal (powered directly from BATTERY and REG/REC according to your diagram). Those light functions should come from AUX so they are only energized with the KEY in the ON/ACC position.

As you have it, they are always powered.

[thirstforspeed]

... i dont get it, how are they wired wrong? they run off the key switch (the main key is the ON/OFF/PARK box in the lower left). nothing is on when the key is off other than the m-unit in order to sustain the alarm. all the lights other than the front light are LED, and the output circuit LED on the m-unit is off. There is no leakage to my plate lights.

and that still doesn't help me understand why the low beam leaks voltage when the key is off.

[FridgeRaider]

Hey guys, thanks for the great input! I was able to put some time into advice-directed troubleshooting today and was able narrow it down to what is causing the issue. I believe it to be the Hi/Low switch being faulty or wired incorrectly. As for a wiring diagram, we don't have a final one on paper. I do remember that I had to solder either the Hi or Low connection in the actual switch because it had degraded, so that might have jostled loose over 6 months of intermittent riding. I haven't had the time yet to check either so in the mean time, I have some questions to help me better understand the M-unit.

This is per the M-unit manual:

In  order  to  save the  vehicles  battery  power  the  head  light  is  always switched  off  after  key  lock  is switched on. The head light will be activated automatically after pressing the start button or (for kick start) after one short light switch operation. If a push buttons is used for high/low beam control, a short push will toggle between high and low beam. Hold the button for 2s will switch off light completely. Press the button again will switch low beam on again. If a switch is used for light control it is only possible to toggle between high and low beam once the light is activated. 

The last sentence is a little confusing for me. With a correctly working Hi/Low switch, should it be able to turn the headlight on (without starting the engine) and then be able to switch between the Hi/Low settings (with the engine still off)? Because that's currently what I'm able to do with it.

The voltage leakage is isolated to when I do exactly as described above, then afterwards: leaving the headlight on, switch on Hi, and then turning the key to off; The bike will honk twice and then have the small voltage leak powering the headlight. When I turn the bike back on, the headlight will automatically come on instead of being off by default. If i turn the key off with the switch on Low, everything works normally as it should.



Another thing to mention is that when the switch is placed on Hi, the input light on the M-unit remains lit. Is it supposed to do this? Or should it momentarily flash and then turn off like it does with the low? Pic of the M-unit when the switch is set on Hi:



Sidenote: Just realizing that it does this, what would make the Turn L Output light stay on like it apparently does in the picture?

[calj737]

... i dont get it, how are they wired wrong? they run off the key switch (the main key is the ON/OFF/PARK box in the lower left). nothing is on when the key is off other than the m-unit in order to sustain the alarm. all the lights other than the front light are LED, and the output circuit LED on the m-unit is off. There is no leakage to my plate lights.

and that still doesn't help me understand why the low beam leaks voltage when the key is off.

What is happening is the m-unit is signaling to you, by virtue of the headlight remaining ON that the battery voltage is low. Thats occurring due to a voltage leak.

Control of the LIGHT function depends greatly upon the type of switch you are using. If, they are the stock "rocker type", then you need to possibly re-configure the m-unit menu to a different option to insure the LIGHT toggles properly.

[calj737]

If a switch is used for light control it is only possible to toggle between high and low beam once the light is activated.

The last sentence is a little confusing for me. With a correctly working Hi/Low switch, should it be able to turn the headlight on (without starting the engine) and then be able to switch between the Hi/Low settings (with the engine still off)? Because that's currently what I'm able to do with it. Yes, this is proper behavior.

The voltage leakage is isolated to when I do exactly as described above, then afterwards: leaving the headlight on, switch on Hi, and then turning the key to off; The bike will honk twice and then have the small voltage leak powering the headlight. When I turn the bike back on, the headlight will automatically come on instead of being off by default. If i turn the key off with the switch on Low, everything works normally as it should. You're conflating 2 events to the wrong symptom. The m-unit will only HONK after it has detected a low voltage condition, not a leak. What you may be experiencing is, a low battery is causing this behavior, not the light switch. Measure the voltage of the battery before riding, after riding, and while toggling the light. I suspect you're not charging properly.


Another thing to mention is that when the switch is placed on Hi, the input light on the M-unit remains lit. Is it supposed to do this? Yes, this is correct. It indicates that a circuit is "active".


Sidenote: Just realizing that it does this, what would make the Turn L Output light stay on like it apparently does in the picture? Youre left side switch is corroded and the turn LEFT is still "grounded".

[thirstforspeed]

interesting. thanks for the insight calj737

my condition must be different then. i don't have a low voltage problem (well, didn't, before i took my battery out for the winter). My m-unit never honked like that when arming the alarm.

my hi/low beam switch is new, and it is a specially wired GSXR switch. it toggles hi and low beams, and otherwise the m-unit operates as expected.

thoughts?

[calj737]

The battery doesn't honk when alarming, only to indicate a LOW VOLTAGE condition.

The GSXR switch is very different from our stock CBs. And the m-unit operates "in reverse" to the way these multi function units do. They have power running to them, then thru the switches. The m-unit does not send power to the switches, instead directly to the component. I've had lots of struggles using multiple controls. I almost always switch (pardon the pun) to momentary switches because its simply a matter of creating "grounds".

Rocker switches also function differently within the m-unit in terms of the features you have to control the lights.

[FridgeRaider]

The voltage leakage is isolated to when I do exactly as described above, then afterwards: leaving the headlight on, switch on Hi, and then turning the key to off; The bike will honk twice and then have the small voltage leak powering the headlight. When I turn the bike back on, the headlight will automatically come on instead of being off by default. If i turn the key off with the switch on Low, everything works normally as it should. You're conflating 2 events to the wrong symptom. The m-unit will only HONK after it has detected a low voltage condition, not a leak. What you may be experiencing is, a low battery is causing this behavior, not the light switch. Measure the voltage of the battery before riding, after riding, and while toggling the light. I suspect you're not charging properly.

Good info to know! Both my dad and I run Shorai Batteries and I have interchanged them on his bike with the same result. I am using Shorai's specific charger for those batteries but I must be missing something simple when trying to charge with it if that's the case.

The only reason I can think of the M-unit needing to discharge voltage would be when experiencing a state of excess voltage. If it is a low battery condition, why would it be the cause of the leak? I don't see them designing it to drain what little power is left in the battery. Also, wouldnt the M-unit sense a low voltage condition and honk without caring what position the hi/lo switch is in?

I just want to make it a point that I am in no way, shape, or form, being critical or skeptical of any advice given. Just trying to play devil's advocate to understand things better  Any and all advice is greatly appreciated. Thanks again!

[calj737]

I don't think the source of the charging problem is the m-unit. Whether it's battery A or battery B, the charging system remains unchanged. You need to measure the battery voltage pre-ride, while revving engine at 4,000 and while off but toggling headlight. Let's verify the baseline first then proceed with m-unit "anomalies".

[scottly]

when the M-unit is turned off by turning the key to off, it leaks power to the headlight. This can be noticed by the faint glow the headlight puts off. If left like this overnight, it will drain the battery completely.

When you turn the key to off, the M-unit should turn off ALL power to the headlight. No ifs, ands, or buts.

[kwaka74]

Hi Fridge Raider.

I'm currently getting a complete rebuild of my 1975 Kawasaki KZ400, and used an M-Unit for the electrical loom rebuild. I used new, but classic 'toggle' style hand controls and found i had exactly the same problem as you.

Specifically, i was finding that when i turned it off completely and removed the key - The M-Unit was bleeding a small voltage, (around 1 volt) from 4 of the outputs once turned off, (headlight hi and lo, brake and aux). This was causing my battery to go flat.

My auto electrician had a look - couldnt figure it out, and assumed that there must be a fault with the M-Unit itself.

After significant digging - i have found the solution.

Stefan from Revival Cycles advised me that:

"We have seen this several times, and it isn't actually a problem... its a poorly designed and documented feature of the m-Unit called a parking light. To activate the parking light you turn the key off with the headlight in the high beam position, then the m-Unit will keep a little voltage on the headlight and the tail light so that they glow dimly. The manual does a poor job of explaining this and even goes so far as to say it won't work with toggle style controls like you have on your KZ. But it does work, and it causes massive confusion and drained batteries all over the world.

To solve the issue, make sure the head light is on low beam when the key is turned off, and double check the headlight is off before leaving the bike. Unfortunately there is no way to disable this "feature".

Hope this helps,
Stefan"

And similarly, Motogadget replied to my description of the issue with:

"Dear Customer,

If you switch ignition off while high beam is on, the parking light feature is activated.
Please read instructions page 4.

Best Regards
motogadget Support Team"

Intrigued, i checked the manual - lo and behold - the paragraph was there - however it didn't explain properly to me how to use the feature on my specific controls:

The parking light feature is activated by pressing the lights push-button or respectively the high beam toggle switch simultaneously while deactivating the main (ignition) switch. The parking light feature is realized by the existing low beam and rear light illuminant. There is no additional parking light lamp necessary. Parking light should no longer activated than 2 hours to prevent draining the battery. Therefore a activated parking light will be indicated by two short honks.

Motogadget munit v2 Manual English 3.3 edition, Chapter 5, Page 4.

Feeling sheepish, i asked whether this feature can be turned off, they replied:

"This feature cannot deactivated.
Just switch to low beam before switching ignition off."

Just as Stefan from Revival Cycles said: It is a poorly documented feature of the M-Unit, with substandard manual instructions on how to use it with non- Motogadget pushbutton controls.
The manual also explains why your motorcycle honks twice - it is a warning to let you know that the parking light is on.

Hope this helps.

[thirstforspeed]

well then. that makes sense (the explanation then, not the implementation).

thank you for shedding some light on this. its good to know that it isnt a fault in my (or a batch of) m-Units.

[FridgeRaider]

Hey kwaka74,

Thank you!!!! That is fantastic information and exactly what is happening. Now I have some resolution to this "issue" and can pass it on to my father the next time he asks me about it.

And thanks again to everyone else with their input!

[kwaka74]

I was able to put some time into advice-directed troubleshooting today and was able narrow it down to what is causing the issue. I believe it to be the Hi/Low switch being faulty or wired incorrectly.

Well at least you know your troubleshooting skills are on point!