Hello all, I've been lurking on this forum for years but today I'm getting stuck in.
Quick bit of background to me I suppose - I've been a Land Rover man for a long time, I've had a 90, 2 110's, a Range Rover Classic that I sold when they were still worth nothing (it seemed like the only option I had at the time!) a 200Tdi Discovery, one other P38 and a TDV8 L322. I am now working through the issues on my current vehicle, a 2001 4.0 HSE P38.
I bought the car dirt cheap knowing it had a few issues but fundamentally it was a solid, well specced car. This brake bulb message has been present since I took ownership. I have fixed almost everything else that was wrong and now I have got to this item on my list!
So, everytime I cycle the ignition, with the first press of the brake pedal, I get a BEEP and a message on the dash that reads 'LH Brake Bulb Failure'.
First check - Do the brake light bulbs work correctly - Yes, they are all operational.
Second check - Quick visual check of the harness and connector block on the LH side light cluster - bit of a mess as there is an aftermarket park distance control box fitted which has an earth connection tapped in to the earth wire for the LH light cluster. Other than that nothing obviously wrong.
Third check - Swap bulbs side to side - No change. Swap bulbs for a brand new pair I had in my tool box - No change.
Fourth check - Thorough clean of the bulb holders and connectors, making sure connections are firm - No issues observed prior to cleaning and after cleaning there was no change.
Fifth check - Notice I have a genuine LR towbar with electrics, dig out a tow socket checking tool, find everything works fine. To rule it out though, I find the the harness plug in the boot by the RH rear cluster that connects the towbar electrical connector to the rest of the harness and unplug it. - No change.
Sixth check (starting to swear now) - Remove boot carpet and trim panels to expose rear light wiring harness on both sides of vehicle, inspect it for any damage, make sure the earth connections to the body are good. Get annoyed just looking at the park distance control box and remove the tapped in earth wire (will tidy all this up later as the park distance thing actually worked really well but it looks like it was installed in a rush!) - Can't see anything wrong and makes no change, still get the LH brake bulb failure message.
Seventh check - check current draw on the left and the right brake bulb wiring (my thinking here is that the failure message is brought on by a difference in current draw on the LH and RH brake bulb circuits - please correct me if I am wrong - I am not a trained 12V elec and in no way an expert on the BeCM, just a general car mechanic that has an interest!) - LH is 1.58A, RH is 1.56A - would such a small difference bring the message on?
Eighth check - Turn my attention to the BeCM, find the connectors and the pins responsible for supplying power to each bulb and just have a quick visual check for any damage/corrosion etc. - nothing to report and no change.
So, that brings me to where I am now, still with a false LH brake bulb failure message, do any of you have any ideas what I could try next to reach a diagnosis?
Any help appreciated.
Many thanks.
Quick bit of background to me I suppose - I've been a Land Rover man for a long time, I've had a 90, 2 110's, a Range Rover Classic that I sold when they were still worth nothing (it seemed like the only option I had at the time!) a 200Tdi Discovery, one other P38 and a TDV8 L322. I am now working through the issues on my current vehicle, a 2001 4.0 HSE P38.
I bought the car dirt cheap knowing it had a few issues but fundamentally it was a solid, well specced car. This brake bulb message has been present since I took ownership. I have fixed almost everything else that was wrong and now I have got to this item on my list!
So, everytime I cycle the ignition, with the first press of the brake pedal, I get a BEEP and a message on the dash that reads 'LH Brake Bulb Failure'.
First check - Do the brake light bulbs work correctly - Yes, they are all operational.
Second check - Quick visual check of the harness and connector block on the LH side light cluster - bit of a mess as there is an aftermarket park distance control box fitted which has an earth connection tapped in to the earth wire for the LH light cluster. Other than that nothing obviously wrong.
Third check - Swap bulbs side to side - No change. Swap bulbs for a brand new pair I had in my tool box - No change.
Fourth check - Thorough clean of the bulb holders and connectors, making sure connections are firm - No issues observed prior to cleaning and after cleaning there was no change.
Fifth check - Notice I have a genuine LR towbar with electrics, dig out a tow socket checking tool, find everything works fine. To rule it out though, I find the the harness plug in the boot by the RH rear cluster that connects the towbar electrical connector to the rest of the harness and unplug it. - No change.
Sixth check (starting to swear now) - Remove boot carpet and trim panels to expose rear light wiring harness on both sides of vehicle, inspect it for any damage, make sure the earth connections to the body are good. Get annoyed just looking at the park distance control box and remove the tapped in earth wire (will tidy all this up later as the park distance thing actually worked really well but it looks like it was installed in a rush!) - Can't see anything wrong and makes no change, still get the LH brake bulb failure message.
Seventh check - check current draw on the left and the right brake bulb wiring (my thinking here is that the failure message is brought on by a difference in current draw on the LH and RH brake bulb circuits - please correct me if I am wrong - I am not a trained 12V elec and in no way an expert on the BeCM, just a general car mechanic that has an interest!) - LH is 1.58A, RH is 1.56A - would such a small difference bring the message on?
Eighth check - Turn my attention to the BeCM, find the connectors and the pins responsible for supplying power to each bulb and just have a quick visual check for any damage/corrosion etc. - nothing to report and no change.
So, that brings me to where I am now, still with a false LH brake bulb failure message, do any of you have any ideas what I could try next to reach a diagnosis?
Any help appreciated.
Many thanks.