I started this discussion, but can't find the original... Adding some factory grips to a 1981 R100 RS. Decided to take the advice of my fellow airheads and go from the switched power in the headlight bucket, to a relay, then to a fused switch.

Got the switch. Got the relay. Got the grips. Now how to make it work? I'm having trouble making the relay work.

1. Switched power #30 (that comes from a power source that is “switched" on ideally. Could also come straight from the battery but what if you forget and leave the grip on?)
2. Ground that first circuit #87

3. Then comes the circuit you want to run - #85. A fused line goes to a switch, and then to the application (switch also goes to ground - two prongs)
4. Lastly the fourth terminal #86… what? goes to ground or to the application as a ground. I think this is where I’m messing up. I have it lashed up to an old battery as a test but the relay won't click on.

I tried just battery, switch, to grips. Then grips to ground and it worked!. But I want to isolate the connector block from this circuit.

Thoughts? Thanks!