My fear has been realized. It was the bane of my existence when I had my 35 year career in telecommunications and I.T. What is it you ask? A system that goes down, with not just one problem causing the outage, but multiple problems, making troubleshooting difficult and sometimes finally resulting in a "shotgun approach".... replacing everything replaceable and getting the system operational again. Usually an expensive proposition.
I received the replacement left heated grip for the first new one I inadvertently broke while installing it. It went on just fine and I metered it afterwards to make sure I still had continuity. 2.4 ohms... perfect! I temporarily wired it in and tested the heaters. No heat. Shit!... time to dig in and do some serious troubleshooting.
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| The pile of parts removed so far. It will be growing |
The service manual is open to the electrical portion and Chapter 17 - Heaters. There is a long step by step process, but with the bike partially disassembled I could test some individual components and "cheat" a bit. First thing was to check both fuses with a meter and neither one was blown open. Next is the heater system relay. The book says to replace it with a known good one. The one for the horn and turn signals is the same type. I did a double test by using the relays to try and operate both systems. Both relays operated the horn and turn signals, but would not turn the heaters on. The grip heaters are wired in series with the rear seat heater. Because the seat was out, I had access to the connector for the rear seat heater. This allowed me to meter the entire grip heater circuit which proved that the throttle grip heater was good. I then metered the rear seat heater and got the normal 2.4 ohms. I then metered the main seat heater elements and found both of them to be good. The seat heaters use thermistor circuitry to ensure the seats don't "get too hot." In the manual, there is a chart that shows thermistor resistance based on temperature. My super duper Klein True RMS multimeter has a temperature probe. It was about 10 degrees C in the garage yesterday, and the chart said the thermistor should read between 90 and 101 ohms. All 4 thermistors read a perfect 98 ohms. It's gotta be chilly when you work on this system or it will not operate.

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| The left grip has the Kuryakyn chrome grip cover installed to protect it |
You'll notice the dashboard and speaker grilles are out. I needed to ensure the potentiometers that control the amount of heat desired by way of controlling the voltage output from the heater control unit were connected. They are located below the LCD screen and just above and on both sides of the ignition key. Something I did not check previously. I found out the service department had that out to do the fork seals according to the service procedure. There is one multi pin connector for the pots and the switches that control the display which were all working. This also allowed me to clean dust and debris from behind the speaker grilles that blows in through the fairing.
So, the next thing I need to do is pull the lower trunk half and then the left saddlebag to access the heater control unit and the main cable connector. I will need to connect all the elements and meter right to the connector. It starts with the basics of voltage and ground, and progresses to the other elements. Hopefully it is a simple wiring issue and doesn't turn out to be the main controller unit.