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Back up fuse

4160 Views 37 Replies 9 Participants Last post by  schancey48
What is the "back up" fuse for on my '07 fjr? It has full time power but can't figure out what it powers. I am still chasing a power draw and I am wondering if it could be the culprit.
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There is a constant small parasitic draw to keep the clocks, etc. alive..... if your bike is going to sit a week or more, recommend plugging it in to a Battery Tender.
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I think we need a picture of that..... not ringing any bells just yet......
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I don't recognize it...... I had a PC and don't recall anything like that...... but I had the simple version, no Autotune or map switch. I guess all you can do is keep digging into where those things are connected.
Check the fuses, in particular the FI fuse. Check for corrosion at the starter relay connector. Several things must make connection for the fuel pump to run..... kill switch, side stand switch, clutch switch, or in neutral. Ignition switch must work too obviously (there was a recall back when). The wiring diagram in the service manual will be helpful.........
Courtesy of a good member here, see post 6. It covers '06-'07
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The wiring diagram could be clearer but gotta slog through it... AFAIK, fuel pump has it's own ground and doesn't go through the spiders. Common ground for fuel gauge and pump.....
Power from Ignition fuse, goes to red/white wire at starter relay... with ignition ON, got power there? Red/blue goes through the ABS 30 amp fuse to the ABS pump relay, should also have power.

The blue/white heads off to the ECU and ABS ECU, with a branch to Connector 52 (8-way in front of engine by steering head) to feed the starting circuit cut-off relay, which is part of the fuel pump relay assembly, then on to the start switch, which basically momentarily grounds that circuit, making the start relay work........ conditional that kill switch is in RUN, side stand up or in Neutral, or if in gear, side stand up and clutch pulled.
It gets a little complicated if you try to figure out how the ECU interacts with the start circuit cut-off/fuel pump relay, but once engine starts, start switch disabled and fuel pump enabled.

You need to verify kill switch, side stand switch at minimum are OK, should work with bike in neutral with no effect from the clutch. See manual 8-13.

If you go into DiAG mode and get to the sensor actuation, d:20 is side stand switch (retracted = ON, deployed = OFF), d:21 is gear position switch (Neutral = ON). No test for clutch switch. See manual 8-53-54.

PS - S4 spider is beside engine/frame, left side (must lift tank and remove T-bar and insulation pad). Gets access to connectors forward of the engine, just ensure they are clean.
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Fuel pump relay is a double relay, combo starter cutoff and fuel pump relay...... the biggest one. Red/blue does go to it from fuel pump..... via the multi-way connector near your steering head I believe.
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