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2014 Honda BF15DK2 malfunctioning indicator lights and buzzer

moderndayhero

New member
Hello everyone. Thanks a million for this forum. I’ve learned a lot from it, but now I need to ask for help.

TLDR; How do I get my engine overheat and oil pressure lights wired up and working as well as the overheat buzzer operational without using the Honda Remote Control?


Now the rather thorough context. Please forgive the detail but it will probably help answer the usual questions. I have a 2014’ish Honda BF15DK2/ SRSU (Short shaft, Remote control, Electric start, Europe destination). We’ve had our boat for 3 years now. The boat was new. The Honda was already used and packaged with the boat, but it didn’t come with the Honda Remote Control. Instead it came with a third-party throttle which based on the design of our little sloop (it’s a Dutch canal boat really) I suppose made some sense at the time of initial fit up. I don’t believe the Honda remote control would fit on our particular console, but that would require some additional research.


Anyway, after various troubles with this engine over these three years I finally realized that (among other things) the engine had been overheating from time to time. This would have been easier to diagnose if the buzzer worked (there actually is a buzzer, but was previously unknown/hidden to me) and if there were any indicator lights which there are not. I didn’t know this engine was even capable of transmitting warning sounds and displaying lights for the first long while. You don’t know what you don’t know, right?


Well, I’ve since learned a lot more about this engine (little thanks to Honda and mostly thanks to the Internet). I know I have the factory wiring harness. I know a buzzer exists and works when I apply voltage directly to it, but doesn’t sound during an overheat condition. Eventually, I suspected a bad transistor in the CDI not completing the path to ground as I’ve tested pretty much everything else (continuity along the wires, etc.) and it all seems to be ok.


I do know that when the engine overheats the engine is forced into limp mode until it cools off, so that part of the CDI is working properly. It was challenging to understand why the engine was behaving the way it was without any other outward indications that it was overheating, but I’m learning now. I decided that I don’t care so much about the buzzer IF I could at least get indicator lights working properly. I finally found a Honda wiring diagram that appears to be exactly the right one for my engine and fortunately I have the Honda wiring harness for it, so from that perspective everything looks spot on. In fact I just installed a WEMA tachometer and it seems to be working perfectly and that wiring diagram was critical in getting that done correctly. I’m super happy there.


My real challenge it seems is with the indicator lamps. Here’s where I really need your help. I naively assumed that I could just order up a couple of 12V LEDs and just plug them in according to the wiring diagram and that would be that. I was hopeful when I plugged in the one for the oil pressure sender. A nice bright green :) My hopes faded when I plugged in the overheat LED. It’s burning just as brightly as the oil pressure one. I’ve taken the multi-meter to task. I’ve measured lots of things, but I can’t make a ton of sense out of what I’m getting back anymore. I even bought a new CDI to test as I was ultimately convinced this had to be where the problem was but that has also failed to solve my issue.


So, I have no idea what to try at this point. I’m reasonably convinced (although not certain - thanks again, Honda documentation) that I’ve wired things up correctly: orange wire for the oil pressure sender, red wire for the overheat, both sharing the grey wire (same one I used for the tach installation). When I short the oil pressure sender the green LED goes from bright to dim, but not out. The overheat sensor is constantly burning bright red regardless of engine condition. And of course, the buzzer does nothing even when I have been certain (in retrospect now) that the engine was overheating.


So. I’m utterly lost folks. What am I missing? Is there logic buried inside the Honda Remote Control (that I don't have) that makes it all work? This wouldn’t make much sense to me as the CDI should handle all of that functionality and neither my original nor brand new CDI seem to behave any differently, but I don’t know what else I can try at this point. Please help me get my buzzer and my two lights working. It didn't seem like this would be a challenging project and yet here I am.


Huge thanks in advance to anyone who has even bothered to read this far :)
Alan
 
Hi Alan,

Very thorough and understandable write up. Thank you for making the effort to state your case so well.

After looking at my BF15D wiring diagram I will tell you that it lists no provision for an overheat warning light. I only see a warning buzzer powered through the ignition switch and grounded through the CDI.

My diagram also indicates that the CDI is connected to a TWO WIRE thermal switch for sensing engine coolant overheating.

This may be a large part of your issue as you indicate that you are working with a ONE TERMINAL temperature switch. You also indicate that you have wired your supplemental LED in the same circuit with the oil pressure indicator. This may be the reason for the oil indicator not working properly as it is completely separate in my diagram.

Keep in mind that my manual and diagrams only cover the American Honda BF15D and I am not sure if the Euro models are the same.

I will be more than happy to list wire colors and their routing for the remote indicators, oil and overheat, if you think that you can use that info. Just let me know.
 
Hi jgmo,
Thanks for the reply! Since Honda stopped using the serial number to provide any sort of engine ID (like, why?) I did manage with some help from the local Honda dealer here in Amsterdam to confirm the model of my engine which is indeed a remote model. The 15hp remote model has provisions for a buzzer, engine overheat indicator, and oil pressure indicator. I'm suspecting that if I had the Honda Remote Control I'd be sorted here (I hope I would!) but that won't be a trivial project. I'd prefer at this point to just finish up the installation myself meaning - run my own indicator lights. But since the buzzer doesn't sound when the engine overheats I fear this is not quite as simple a job as I had originally envisioned.

And yes, apologies if I wasn't clear. There is indeed a two wire connector for the overheat sensor (which I replaced just in case although I've since confirmed the original sensor to work perfectly.)

Interesting comment regarding the wiring that your diagram shows. My diagram shows only three wires going into a box labeled "Indicator Light". Orange, Grey, and Red. The grey wire is quite clearly the very same signal wire that also carries hertz for the tachometer (which is working well). That wire also carries voltage. I've not been able to conclusively determine if the red or orange wire is for engine overheat or oil pressure or vice versa, but I have a fairly high level of confidence at this time that indeed red is for overheat and orange is for oil pressure. Of course I'd be delighted for someone to prove otherwise here. Perhaps notable is that from what I can tell the CDI for the BF15D has not changed since 2003!

But if you're showing completely separate circuits then it stands to reason that either I've got the wrong diagram or a very different engine. Unfortunately, it is my suspicion that it is the latter versus the former. I've definitely got a factory Honda wiring harness and it matches color for color, lead for lead the diagram that I have.

Could you share your wiring diagram? I'm curious now. Also what age is your engine?

Alan
 
Hi Alan,

Ok...here goes!

You are correct....I missed that the LIGHT INDICATOR is obviously a module containing the green oil pressure light (on when oil pressure is "good") and the overheat red light. My apologies. I haven't used my boat in quite a while.

My diagram is old....5th edition..issued in 2002....and doesn't list the 10amp instrument fuse. I bought it in 2016 but never noticed that before! I own a remote 2006 BFD20.

Other than that one fuse, our manuals are the same.

After taking another look at the circuit for the indicator lamps, it seems that they are both powered through the gray wire and grounded through their respective red and orange wires via the CDI.

The gray wire is powered by the SE THERMAL VALVE HEATER COIL via the brown wire and, ultimately, the yellow/black wire. The Y/bl.wire also feeds the end terminal of the CDI. Probably to turn it "ON".

I have only looked at the thermal valve heater coil voltage while troubleshooting the enrichment valve on the carburetor. I don't remember the voltage but it is, of course, ac volts. I seem to recall seeing something in excess of 24 vac and I'm sure that it increases with engine rpms.

The warning buzzer, on the other hand, seems to be 12 vdc switched from the ignition and grounded by the CDI via the Y/G wire.

If...IF... I'm right about that then you may be able to wire in your RED LED parallel to the buzzer but you still won't have a green oil pressure indicator lamp.

Check this "theory" out and let me know what you think.
 
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Remote controlled : Overheat ,Green/black and Red/blue. Oil pressure: Yellow. Indicator Light : Red , Green ,Orange Tiller Handle model : Overheat Green/Black and Red/blue. Oil pressure: Yellow.Indicator Light : Black and Orange this is for the D models There was never a SRSU model made if you have power /tilt It will be SRTU .the U means its a European model .
 
Sorry folks. Was a busy week. @Tegweni - Yes, G/Bl and R/Bu back to the CDI for overheat. Y for oil pressure also back to the CDI. Indicator lights are R(ed), Gr(ay - not green), and O(range) to the remote control unit. Regarding the model identification - this is interesting. More closely studying the manual I've noticed what appears to be an inconsistency regarding how Honda classify the models. Using their own model matrix I seem to have a "SRU" or is it "SRS"? Something doesn't match within their own nomenclature. Then just to keep it interesting using the TYPE CODE (Example) on the very same page I have "SRSU" which they map to S=Short Shaft, R=Remote Control, S=Electric Starter, U=Europe. Anyway I think that gets us more or less on the same page so to speak. I don't suppose you know what the Red, Gray, and Orange wires for the indicator lights map to precisely?
 
@jgmo (apologies for the delayed response)
> After taking another look at the circuit for the indicator lamps, it seems that they are both powered through the gray wire and grounded through their respective red and orange wires via the CDI.
This was my initial assessment as well. Unfortunately, I don't think it's so straightforward because then this would be all pretty simple to wrap up. I actually get varying amounts of voltage across all three wires. Red and Orange originate at the CDI and terminate at the remote control unit (which I don't have). The Gray wire comes from a Y/Bl wire being fed by the regulator/rectifier. That's pretty much gotta be the power source, right? So, if the CDI just did something simple like default grounding of the wire that corresponds to the oil pressure sender and vice-versa for the overheat I'd be golden. Problem is both lights are always on. This condition persists across the original CDI as well as the new one I recently purchased and installed. And, FYI - if I short the oil pressure lead it only makes the test LED I've wired up a little dimmer - it doesn't even go out completely.

The warning buzzer is indeed 12VDC, but I'm very much intrigued about the VAC piece. I'm not a EE (which is likely part of my problem here), but I never would have guessed there to be any AC coming from this. But now that I consider it I suppose that's what the rectifier is doing? Converting VAC to VDC (and charging the battery)? Probably given the nature of the coil it could only generate VAC, but I'd have to dig in to understand that better, but that's pretty interesting alright.

Regarding your theory. I think I follow what you're suggesting. I could pretty easily wire up my own circuit off the overheat sensor to burn the lamp in an overheat condition which might be a worthwhile endeavor and I've considered it a couple of times now. The fact that the buzzer doesn't sound when it should...or ever for that matter had me staring again at the CDI thinking "this must be the root of the trouble because there's simply not much else here", but two CDIs in and no change/improvement with any of this has me scratching my head.

I mean really - how hard could any of this actually be, right?!?

This is why I've been trying to get info on the remote control unit. While I can't see the logic in how that would/could/should make any difference in any of this I just don't know what else I'm missing.
 
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I've been speaking with some folks about this. An interesting theory recently surfaced suggesting the possibility of a poor ground connection somewhere as the culprit. I'll do what I can to chase this one, but it won't happen until spring I'm afraid. Nevertheless, I'll report back here once I get back to it.
 
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