Heated grip wired to taillight

Yesterday, I had a generic heated grip installed at a local bike shop. The installer tapped the tail light for the power source. I looked at the fuse at the tail/stop light and it has a 15amp fuse. The heated grip works well and has HI/LO setting and gets really hot. The grips draws 3 amp at max setting.
Am I overloading the circuit at the tail/brake light or will it be fine?

Is there a relay in the circuit? I use the tail light wire to trigger the relay, but have a separate power line.

If you aren't blowing the 15 amp fuse, you aren't overloading the circuit. I would be tempted to put a 5 amp fuse in the line to the grips.

IMO like Cone did, it's best to run the grips right to the battery through a simple automotive relay that can be triggered by the tail light circuit w/in line fuse.

In the installation manual, it states "electrical switch is protected by relay" I'm assuming ( not sure) the relay is built into the control switch. Does this mean I don't need to install extra fuse on the grip? I rode for about an hour with the heat setting at the highest level and the tail/brake light worked fine. Just concerned if I may damage the electrical system or cause a fire.

They probably installed a relay somewhere and are triggering it from tail light, like BR said.
I wouldn't run grips directly off that cirquit regardless of whather it does or doesn't have enough juice in it.
You can confirm that by tracing the grip wires.
If there is no relay, I'd either rewire it myself or ask 'them' to do it the right way.

I just wired a couple of bikes recently... Including two VFR's.

The tail light should be used to trip the relay to the on position.
The grip draw more AMPs the the 18-22 gauge tail light wire can handle.

This is the diagram I use for wiring electronics to a bike:
Power Source = Tail Light
Control Unit = Fused panel block
Ground
Power Source = Battery
I use a 25Amp breaker for the main then set my desired fuses in the power block.

When you are done you only have two positive and two negative coming off the battery.
All of your farkles will be fused.






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