F650GS heated grips problem: 7.3V at connector regardless of switch position


Registered user
Jul 5, 2013
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Ahoy, I know there are a fair few grip threads already, including a recent one, but I have specific shenanigans to report that may intrigue sparkies.

I have a 2012 F650GS (the 800 twin) with the two-position heated grip switch on the RHS bars. I've been having erratic issues with the grips either both working, or neither working (i.e. not the common LHS failure of wiring), but both have now given up completely.

The battery is new, 12.65V off, 14.5V across the terminals when running.

At the switchgear connector, I have continuity to the expected pins (black/blue, and black/brown) for both heat settings. The wiring looks intact and not pinched anywhere. Disclaimer: I haven't checked the pins at the ECU end, I'll go and do that now.

At the grip connectors, on the heating element side I have continuity and about 8Ω

However, at the bike side connector, with the engine running I see a steady 7.3V - when the circuit is open - on both sides, regardless of switch position. Off, mid, high, no difference. Wiggling the front end wiring doesn't produce any change.

Now, that should give about 6W per grip, but they're stone cold on any switch setting.

My working theory is that the open-circuit voltage is fraudulent and the bike isn't actually providing that with resistance on the circuit. That points to a problem inside the ECU, i.e. forget it and go aftermarket (I have heated gloves on the way).

Does this ring any bells? Is there anything else I should be trying, other than checking the switch continuity at the ECU end of the loom?

Thanks in advance for any suggestions.
BUMP. I had continuity at the ECU end as well, so the problem is inside the brainbox. Aftermarket heated grip-wraps it was then. The biggest hassle was finding a point to get +12V for the relay without fuses to tap off, I bodged a tap into the sidelight.

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