Power Relay

Tuesday, Oct 22 2019 [2,358 miles]

I did some reading after installing my heated grips and noticed that although there are two places to connect to ACC2 (switched 12V power) there is only one ACC2 fuse. The fuse is rated for 10 amps. I don’t know the draw of the heated grips, but I bet if I ran grips, heated liner, and heated gloves at full power I’d exceed 10A.

A solution is to convert ACC1 (unswitched 12v power) to switched and use it to connect heated gear. A 12V automotive relay can do that job. I got a socketed waterproof relay which was almost too big to fit in the available space. I probably could have gone with a smaller (in physical size) relay. The relay is rated at 14v/30A.

Wiring is simple. I crimped on the needed connectors and pluged everything in as noted in the schematic.

Relay Schematic

Relay Schematic

-> 30 (Red) 12v unswitched positive (ACC1 Yellow/Red)
-> 87 (Blue) 12v heated gear positive
-> 86 (White) 12v switched positive (ACC2 Black/Red)
-> 85 (Black) 12v switched negative (ACC2 Brown)

-> 87A (Yellow) is unused
-> 12v unswitched ground (ACC1 Brown) is tied to heated gear ground

Note: colors match my relay. Other relays may use different color codes

Relay socket

Relay socket

Relay socket
Connectors added

Connectors added

Connectors added
Relay installed

Relay installed

Relay installed

That did the job. Turning the ignition on triggers the relay when ACC2 is energized. That lets power flow through the relay from ACC1. I won’t have to worry about a drained battery because I forgot to turn the heated gear controller off.

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