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Discussion Starter · #1 ·
Any one found a diagram showing all the components etc and what each one does?

My left hand reversing light will not go off. I suspect wiring in a small halogen reversing lamp has overloaded the tiny relay and fused it closed. The light now stays on and will flatten the battery.

For the moment the left hand lamp is disconnected, and the BeCM shows it as being blown.

Thanks

Jeff
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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They aren't powered by relays - but are driven by MOSFETs on the power board. It is possible the MOSFET has failed in an on state.

There are no circuit diagrams (at least that are publically available) of the BECM boards unfortunately.. I keep looking and come up with squat every time...

Where are you located? If in the UK then I can probably repair it for you if you send the board to me. I've got a load of spare ones kicking about from damaged BECMs

Marty
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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Hopefully this will help... I've marked on the picture below which one is LH Reverse for you.

The MOSFET in question is a BTS410E2 (on the board I looked on) but could also be a BUK203-50Y

Electronic engineering Cable management Electronic component Electrical network Electronics


I think the BTS version is still available - but if you can't get a hold of any then let me know and I have some working spares that I've recovered from a couple of damaged boards.

Hope this helps...

Marty
 

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1995-2002 Range Rover P38A
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Marty,
Is it at all possible that the Becm is getting a bad signal such as an earthed control line that is switching on just one reversing light?
Seems farfetched, but could be corrosion and oxide tracking in a connector?
 

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LEGACY VENDOR
1995-2002 Range Rover P38A
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Unlikely I would imagine as the MOSFETs use a high level input (up to vBatt) to activate it, rather than a ground signal to turn it on.

It could be that there is a problem in the wiring somewhere which is causing the lamp to stay on (external to the BECM)

Anything is possible though.. it could also be corrosion around the MOSFET itself that is leaking power from the 12v supply to the input pin, switching itself on when it shouldn't be.

A visual inspection should be able to see and surface corrosion though.
 

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1995-2002 Range Rover P38A
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+1 on the corrosion as it would not take much leakage to pull up the Fet.
Thanks for the clarification. Fortunately (Touch Wood) I have not had to delve too deeply into the Becm's on mine, so I was not sure if they were B+ or earth biased...Now I know!
Cheers!
 

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LIFETIME CONTRIBUTOR
2002-2005 Range Rover MkIII / L322
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If needs be, there is a chap in Sydney who repairs BeCMs. He's Rupert Prior on this forum. I note he hasn't been here for a while but he does frequent the AULRO forum.
 
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