Key Switch Problems!!! HELP!!!

[meangreen450r]

Ok guys, my kfx battery was drained, wouldnt do anything. When I hooked the charger up to the battery, with key switch turned off, the fuel pump kicked on, like if i had turned the key on! Im thinking my key switch has went bad, any help will be greatly appreciated! Thanks Adam

[Duster]

Well, it can be several things... but the 2 most likely are these...

1- bad key switch (easy to test)
2- fuel pump relay STUCK in the closed position
3- don't wanna get into that yet


So charge the battery up... fire the thing up... then turn off the key. If it shuts off, it's not likely the key.

You can also officially test the key switch. Under the hood on the switch side there is a velcro bag. If you trace the switch wire back into this bag, you will find a connector.

Disconnect this connector. If you have a multimeter, put the probes in the plug to check for a continuity beep. Switch the key on/off. It should only beep in the on position... else it is bad.

If you don't have a meter, still do the same as above. While the key switch is disconnected, remove the negative battery cable. Then touch it back. Do it a few times and listen for the fuel pump to prime. If it does... bad relay.

If it does not, hook key switch up again, LEAVE OFF, turn thumb switch ON, and touch battery cable back again. If you can get it to prime this way and not the other... bad key switch.

You can double confirm this by trying a 3rd time with the thumb switch off. If it does not prime... bad key switch.



In the end, the fuel pump relay is retardantly connected to direct battery power before the key switch. But the relay is normally open, not letting power through... until you turn the key on and thumb switch. The voltage that closes the relay to energize the fuel pump comes through the key switch and thumb switch. But if the relay gets stuck closed, you are screwed because it does not need the relay voltage anymore.