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Reversing light parasitic current


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My reversing light is draining my battery, but I don't understand how, and I don't know how to fix it. Any suggestions would be much appreciated.


My car has been consistently draining its battery when it's parked up. I initially thought it was just because I'm not driving it much (COVID) and just replaced the battery thinking it would go away, but it has not. The car draws 0.07A without the keys in, which with the size of my battery means it's dead flat in about 24 days... not great. I've unplugged the fuses one-by-one and found f8 - reversing light drops the parasitic current to zero. The reversing light is off without the keys in, and appears to operate normally with the engine turned on! 


Anyone have any idea what might be the problem? Car is a 2007 Honda Jazz.




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Hi, I've had a look around and it seems fuse f8 does more than reversing lights. Try turning on everything in turn with that fuse out to see what its protecting...


I also had a current drain with the car locked, turns out it was Bluetooth module not shutting down...


Does yours have Bluetooth/hft? These are very well known to fail. In the accord the module is right behind and above the centre air vents, don't know if yours will be...

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Thanks Charlie, you're right. The Haynes manual lists f8 as reversing light, but the circuit diagrams in the same Haynes manual show f8 in circuits for the audio system, instrument panel and speed sensor but not the reversing circuit.


My Jazz doesn't have bluetooth as far as I know, but looks like you might be along the right lines with the audio system.

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Hi Luke, glad you're getting somewhere.

Its the awkward part next, disconnecting the various systems this fuse is running to find the culprit!

My monies on the audio system, or something else that needs a permanent live when the cars off...

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