Inertia Fuel Cut Switch - Battery Drain

DTd5 · May 4, 2013

I have 0.33A (330mA) current measured against Fuse No. 5 in the fuse box under the drivers seat, this is causing the battery to slowly drain over a number of days.

If I use the landy every few days, its not a problem, but if I leave for more than about 5 days, then the battery will be down below 12v meaning it won't normally start.

Doing some further investigation today I found that if I removed the Multi-Plug from Fuel Cut off Inertia Switch, the current across Fuse 5 instantly disappeared.

Does this mean I have a faulty inertia switch?

DTd5 · May 4, 2013

OK, taken the inertia switch off and pressing the button on top does nothing??

When I take off the rubber covering, and stick a screwdriver down inside I can lift what looks like 2 no. hinged metal plates up. When I reconnect the multiplug, the current stays at zero, but as soon as I press the button which pushes the hinged metal plates back down, the current drain is back at 0.33Amps.

So with regards to the inertia switch, is it correct that it will only press the contacts down and not release them back up?

And how should the contacts be, up or down?

If up, problem solved, if down, then I still have a problem!

Dippypud · May 4, 2013

DTd5 said:
OK, taken the inertia switch off and pressing the button on top does nothing??

When I take off the rubber covering, and stick a screwdriver down inside I can lift what looks like 2 no. hinged metal plates up. When I reconnect the multiplug, the current stays at zero, but as soon as I press the button which pushes the hinged metal plates back down, the current drain is back at 0.33Amps.

So with regards to the inertia switch, is it correct that it will only press the contacts down and not release them back up?

And how should the contacts be, up or down?

If up, problem solved, if down, then I still have a problem!

With the switch fitted, (I'm assuming the impact inertia switch in the middle of the bulkhead), do you get some lights on the dash that aren't normal, the fuel pump doesn't run and the temp gauge goes right up ? ...

sierrafery · May 4, 2013

the inertia switch is normally closed... as long as the car starts the switch doesnt have a problem...this is a simple switch which opens on a bigger impact then you must arm it back manually... being a switch it can cause drain itself but as you unplugged it you interrupted the circuit after it to the engine management...if you want to isolate the drain you must watch the diagram and unplug involved connectors one by one untill the drain stops...then you'll know in which part of the circuit is the problem...i can't help you more if it's a defender

Dippypud · May 4, 2013

sierrafery said:
the inertia switch is normally closed... as long as the car starts the switch doesnt have a problem...this is a simple switch which opens on a bigger impact than you must arm it back manually... being a switch it can cause drain itself but as you unplugged it you interrupted the circuit after it to the engine management...if you want to isolate the drain you must watch the diagram and unplug involved connectors one by one untill the drain stops...then you'll know in which part of the circuit is the problem...i can't help you more if it's a defender

Thanks for explaining that clearer than I could -
Wasn't sure if OP had 'popped' it or not ...

DTd5 · May 4, 2013

sierrafery said:
the inertia switch is normally closed... as long as the car starts the switch doesnt have a problem...this is a simple switch which opens on a bigger impact than you must arm it back manually... being a switch it can cause drain itself but as you unplugged it you interrupted the circuit after it to the engine management...if you want to isolate the drain you must watch the diagram and unplug involved connectors one by one untill the drain stops...then you'll know in which part of the circuit is the problem...i can't help you more if it's a defender

Yes thats the plan of attack that I, but effectively the circuit drawings just show fues No. 5 connecting to the Inertia Switch; Main Relay and ECM, so there are not many things i can actually check

Removing the multiplug from the inertia Switch and/or removing the main relay both stop the current drain, so it is definately on this circuit (somewhere).

Next things is to try and locate all the earth points.

And yes its a Defender

DTd5 · May 4, 2013

Dippypud said:
Thanks for explaining that clearer than I could -
Wasn't sure if OP had 'popped' it or not ...

You will be glad to know that I diddn't pop it whilst driving

Inertia Fuel Cut Switch - Battery Drain

DTd5

Active Member

DTd5

Active Member

Dippypud

Never Knowingly Understood

sierrafery

Well-Known Member

Dippypud

Never Knowingly Understood

DTd5

Active Member

DTd5

Active Member

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