[rockinpirate]

CANBUS is a data bus (network) used for signalling. After doing some thinking, I believe the reverse circuit is probably on the CANBUS since there's a reverse signal line in the stock stereo wiring harness. And since the bulb is part of that circuit, I can imagine that a non-CANBUS bulb could cause issues. However, no idea how the airbag sensor is involved?!

Regardless, I would suggest a CANBUS bulb, and something that at least claims "low RF interference" or "low EMI". I doubt you need a resister in this location so I suggest you just try that first. If it still doesn't work, then either a 3157 with CANBUS and a built-in resister, or an external resister. Built-in resister is easier, but these have a fan on them that would be inside the back-up light enclosure, and I'm not sure that this enclosure is ventilated at all, so the bulb might not last as long as it should, or may cause excessive heat build-up.

I appreciate all the info, JohnnyG. There are a lot of electronic applications I have a good working knowlege of (like musical equipment, etc), but this ain't one of them. lol And I'm certainly not an electrician, either. So all help is very much appreciated.

I have contacted Siriusled and Viper Lighting, and explained the problem in detail. Both have been good at communicating. I'm not worried about the 10 bucks, or so. I would even go to local auto parts store, if necessary. Right now, I'm ready to install the map, trunk and license plate LED's, but I'm not going to until I hear back from seller. I haven't heard of any problems like this for the map or trunk lights, but I'll wait for Viper to let me know for sure.

I bought the reverse 3157 LED from Siriusled, and they have offered to send me another "style", but I don't exactly know what they mean by that, so I have asked for an explanation..... As you said, if it's not a CANBUS, I'd be skeptical of accepting it as a replacement. Thanks, again.

 

[JohnnyG]

Still thinking it through...if the LED bulb you tried is "eating" the CANBUS data, then it could actually be messing with your airbag sensor signalling! Missing link

 

[rockinpirate]

I'm at the point that I don't care how the watch is made.. Just tell me what time it is!

 

[rockinpirate]

Well, Siriusled refunded my money, and I get to keep the pair of 3157 LED's. Doubt I'll ever find a use for them, but I guess he figured s/h cost more than the lights did...

SO I'm all ears and eyes for recommendations for a reverse LED that actually works without interfering with any other electronics. Thanks in advance.

 

[JohnWR]

The Sky does not have any monitoring built in to any lighting circuit with the exception of the turn signals, so the CANBus LEDs are unlikely to do much except burn out faster than standard LEDs. They may eliminate the glow that occurs in the under-mirror map lights and possibly the back-up light, and they may eliminate the problem with the back-up camera, but will not prevent the hyper-flash that occurs when the turn signal bulbs are replaced with LEDs.

 

[rockinpirate]

The Sky does not have any monitoring built in to any lighting circuit with the exception of the turn signals, so the CANBus LEDs are unlikely to do much except burn out faster than standard LEDs. They may eliminate the glow that occurs in the under-mirror map lights and possibly the back-up light, and they may eliminate the problem with the back-up camera, but will not prevent the hyper-flash that occurs when the turn signal bulbs are replaced with LEDs.

Thanks, John, as always. I'm learning as I go.

 

[JohnnyG]

The Sky does not have any monitoring built in to any lighting circuit with the exception of the turn signals, so the CANBus LEDs are unlikely to do much except burn out faster than standard LEDs. They may eliminate the glow that occurs in the under-mirror map lights and possibly the back-up light, and they may eliminate the problem with the back-up camera, but will not prevent the hyper-flash that occurs when the turn signal bulbs are replaced with LEDs.

CANBUS for our cars is not about monitoring the bulb's health...it's about the signalling that travels over the electrical system. When our cars are put into reverse, a CANBUS signal is sent out to tell well, the rest of the car, that it is in reverse. CANBUS bulbs are not about telling the car that the bulb is healthy - it's about NOT interfering with the signalling.

"Hyper-flash" has nothing to do with CANBUS - it's about resistance in the circuit. If the circuit resistance is below "X", a bulb must be out.

 

[JohnWR]

CANBUS for our cars is not about monitoring the bulb's health...it's about the signalling that travels over the electrical system. When our cars are put into reverse, a CANBUS signal is sent out to tell well, the rest of the car, that it is in reverse. CANBUS bulbs are not about telling the car that the bulb is healthy - it's about NOT interfering with the signalling.

"Hyper-flash" has nothing to do with CANBUS - it's about resistance in the circuit. If the circuit resistance is below "X", a bulb must be out.

I believe that you are incorrect.

First, CANBus is a very robust and fault-tolerant system, and an LED id not going to interfere with it. Further, people have been using standard LEDs in these cars for over a decade with no interference issues.

When an automatic transmission Sky is put in reverse there is one CANBus communication between the ECM and the BCM that then operates the relay to light the reverse lamp. With a manual transmission there is a switch that lights the reverse lamp and there is no CANBus participation at all.

 

[JohnnyG]

Not a compelling example as the stereo harness has reverse signalling - even for manual shift cars. On the Axxess interface I bought, the reverse signal comes out of the interface box, which is a clue that it's decoded from CANBUS data. Here's what we know from the wiring diagrams: when the car is put into reverse, +12V is applied to the ECM. What we don't know is how the reverse signal gets to the stereo wiring harness, but looking at the wiring diagram for this, there is no wire for reverse signalling, but there is a "GMLAN SERIAL DATA" wire. So from what I see, it does indeed appear that there is CANBUS signalling for reverse even on manual shift cars.

 

[JohnWR]

Not a compelling example as the stereo harness has reverse signalling - even for manual shift cars. On the Axxess interface I bought, the reverse signal comes out of the interface box, which is a clue that it's decoded from CANBUS data. Here's what we know from the wiring diagrams: when the car is put into reverse, +12V is applied to the ECM. What we don't know is how the reverse signal gets to the stereo wiring harness, but looking at the wiring diagram for this, there is no wire for reverse signalling, but there is a "GMLAN SERIAL DATA" wire. So from what I see, it does indeed appear that there is CANBUS signalling for reverse even on manual shift cars.

LNF cars have an ECM input that may well end up on the bus, but the LE5 cars do not, and my point is that it is incidental to and not used for reverse lamp operation. And there have been no instances discussed where LEDs caused any problems beyond hyperflash or a faint glow when powered off. AXXESS modules have been known to misbehave in Kappas, likely because they were among the first GM vehicles to use CAN, it is not fully integrated into the vehicle systems, and the modules are not seeing the communication that they expect.

I am interested in knowing whether @rockinpirate 's reverse camera trigger is coming from a communications module or from a direct connection to the reverse lamp circuit.

There is a lot of bad information out there, and CANBus LEDs are a part of it. There is a belief that CANBus is the feature of a vehicle that detects and warns of failed bulbs, but that is not the case. There are vehicles that monitor bulbs and give warnings about failed ones, but the Kappas are not among them. CANBus in the Kapps is strictly used for communication between the major vehicle systems and so far has been immune to external influences.

 

[JohnnyG]

The wiring diagram shows the ECM signal as "2.0L & M/T". Plus the Axxess interface (and similar) has a reverse wire available for all models, so seems to be on CANBUS regardless. Totally agree with the incidental, but I'm working on the assumption that the OPs head unit is "confused" about whether the car is in reverse or not. The only variable is the bulb.

And yes, LOTS of misinformation and confusion on CANBUS bulbs on the internet! Conventional wisdom though is that if the car has CANBUS, use CANBUS bulbs. It's not for telling the car the bulb is healthy because a standard factory bulb has no CANBUS circuitry in it!

And just to be a total jackass , if you capitalize CAN, you should also capitalize BUS and it stands for Binary Unit System!

 

[rockinpirate]

Not trying to pour gas on the fire, but here's my latest update........
I replaced the incandescent bulb with the LED, again, and made sure the socket was clean, and the LED was secure and straight. SAME RESULT. So, I put the incandescent bulb back in. Radio head and display are back to work normally.

In the meantime, I installed LED's in my map lights, trunk light, and license plate light. It had zero effect on the radio display or performance at all. NOTE: The reverse light was a different brand from a different source, than the interior, trunk, and license plate LED's. So, I'm still looking for a reverse LED, that will not affect anything adversely. Also note that the camera and LED reverse light works in reverse. Only in forward gears does it affect the radio. Thanks.

 

[JohnWR]

The wiring diagram shows the ECM signal as "2.0L & M/T". Plus the Axxess interface (and similar) has a reverse wire available for all models, so seems to be on CANBUS regardless. Totally agree with the incidental, but I'm working on the assumption that the OPs head unit is "confused" about whether the car is in reverse or not. The only variable is the bulb.

And yes, LOTS of misinformation and confusion on CANBUS bulbs on the internet! Conventional wisdom though is that if the car has CANBUS, use CANBUS bulbs. It's not for telling the car the bulb is healthy because a standard factory bulb has no CANBUS circuitry in it!

And just to be a total jackass , if you capitalize CAN, you should also capitalize BUS and it stands for Binary Unit System!

"Conventional wisdom" is usually anything but, and the more reasonable sources I have found refer to CAN LEDs being needed for bulb diagnostics only. The real fallacy is that attaching CAN to an LED is totally worthless because you are correct that the bulbs do not have CAN circuitry in them. As I attempted to state earlier, many modern vehicles have circuitry that monitors bulbs and it is those vehicles that require the CAN LEDs to prevent spurious "Bulb Out" messages, but the actual monitoring of the bulbs is not done directly with CAN.

Robert Bosch's original CAN documentation refers only to CAN (Controller Area Network) and it seems that "bus" was added later as a redundancy, since a "bus" is another name for a "network". I have never seen BUS used in any technical documentation related to CAN. I have seen CAN, CAN Bus, CAN bus, and occasionally CANBus, but I suspect that latter one is actually not anything sanctioned by the creators or ISO.

 

[JohnWR]

Not trying to pour gas on the fire, but here's my latest update........
I replaced the incandescent bulb with the LED, again, and made sure the socket was clean, and the LED was secure and straight. SAME RESULT. So, I put the incandescent bulb back in. Radio head and display are back to work normally.

In the meantime, I installed LED's in my map lights, trunk light, and license plate light. It had zero effect on the radio display or performance at all. NOTE: The reverse light was a different brand from a different source, than the interior, trunk, and license plate LED's. So, I'm still looking for a reverse LED, that will not affect anything adversely. Also note that the camera and LED reverse light works in reverse. Only in forward gears does it affect the radio. Thanks.

How is your radio connected to the reverse lamp circuit?

 

[rockinpirate]

No idea....
All I know is what I have previously posted. Everything works perfectly with incandescent bulb, and all the other LED's do not affect anything. Plus the camera and the LED work when you put the car in reverse. Also, the radio works when in neutral. Only when you put it in any forward gear does the screen go to "NO VIDEO SIGNAL". Sorry I can't be more helpful, but that question is over my paygrade.

 

[JohnnyG]

Got to focus on the facts we have available. When the LED bulb is installed, it messes with the head unit. When the LED bulb is removed, the head unit functions normally.

The head unit trigger for reverse is either provided by whatever stereo harness interface was installed in the car, or tapped into the reverse 12V circuit. We don't know which.

If the head unit reverse trigger is tapped off the reverse bulb, why would the bulb resistance matter at all? The head unit would just be looking for +12V. When the car it put into reverse, there will be a +12V differential to chassis ground - always (unless of course the fuse is blown, wire broken, etc). Even if NO bulb was installed at all.

On the other hand, if the head unit trigger comes from the stereo harness interface, this signal likely originates from the CAN (as far as we can tell, since nothing else seems to deliver such a signal to the stereo harness).

What I suspect is happening is that this signal is being held high by CAN, so the head unit thinks the car is in reverse, but the camera itself is powered by the bulb circuit and so, when the car is not in reverse, there is no power to the camera and therefore "no video signal". Now WHY the bulb might be causing the CAN signal to be held high I cannot tell you, but Occam's razor leads me to suggest trying a CANBUS bulb

 

[rockinpirate]

I'll try anything! It's only pocket change. lolI know a lot of folks use JDM Astar, but they are not CANBUS. I'll do some more surfing tonight. Headed out, now. Thanks.

 

[JohnWR]

I am assuming that the camera trigger is wired to the reverse lamp circuit. My suspicion is that there is a leakage current from the camera trigger and the high-resistance LED is resulting in a voltage that is triggering the head unit but is not enough to power the camera. The head unit thinks the car is in reverse but isn't getting a signal from the camera, so the screen is blank.

A resistor that would normally be used with an LED brakelight bulb, wired in parallel with the standard LED, should fix the problem.

A "CANBUS" LED would also fix the problem if it has a sufficiently lower resistance than a standard LED, edit: This article ( Canbus proof, what is that really? ) states that the CANBUS LEDs do include a resistor to increase the operating current, so the question is whether the resistance is low enough.

CANBUS PROOF LED LIGHTS

To solve this deception on the on-board computer there are several possibilities. For example, it is possible to place resistors on your vehicle to fix error messages on the dashboard, canbus messages or a blinker. Often this error message can be solved easily.

In addition to resistors, TRALERT® also offers canbus proof LED bulbs, where the remedy for this fault is already built into the bulb. These LED lamps are called CAN-bus proof LED lights.

 

[JohnnyG]

The problem exists only when the car is not in reverse, and your own review of the wiring diagram shows that voltage is applied via mechanical switch in the tranny, which is either entirely on, or entirely off. I don't see how an open circuit could be affected by connection of a reverse trigger wire that's basically grounded?

Saying LED bulbs have a higher resistance is incorrect. They really have no resistive value. They are diodes. Current is all that matters. When it comes to the turn signals, what matters load, not resistance. The BCM is expecting a certain load that most LEDs don't satisfy. To stop the "hyper-flashing", we increase the load on the circuit by adding resistance. I don't really know what bulb circuits are checked for load in the Sky/Solstice, but I suspect it's only the turn signals.

Interesting exchange. We really have no clue how rockinpirate's system is wired, so it's all just guesses, really

 

[rockinpirate]

The problem exists only when the car is not in reverse, and your own review of the wiring diagram shows that voltage is applied via mechanical switch in the tranny, which is either entirely on, or entirely off. I don't see how an open circuit could be affected by connection of a reverse trigger wire that's basically grounded?

Saying LED bulbs have a higher resistance is incorrect. They really have no resistive value. They are diodes. Current is all that matters. When it comes to the turn signals, what matters load, not resistance. The BCM is expecting a certain load that most LEDs don't satisfy. To stop the "hyper-flashing", we increase the load on the circuit by adding resistance. I don't really know what bulb circuits are checked for load in the Sky/Solstice, but I suspect it's only the turn signals.

Interesting exchange. We really have no clue how rockinpirate's system is wired, so it's all just guesses, really

What we do know is that simply changing to an incandescent bulb fixes everything. That's all I know.