Rear Lightning

[sharpy]

I’ve got a 65 plate partner and I’m trying to fit 3 led strip lights in the rear. Will I need a canbus resistor? Tried wiring in but it’s not liking it.

Any advice???


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[Sol]

Yep, if wired in parallel with the existing lights. They're all CANBUS. What did it do? Bulb failure warnings?

[deejay_xb]

Yep, if wired in parallel with the existing lights. They're all CANBUS. What did it do? Bulb failure warnings?

are you sure that all bulbs are canbus? because i had a bad/burned brake light bulb and no warning on dashboard..

[sharpy]

When tested with a spare strip light it does work. Then stops, light doesn’t work and then the original light won’t work.


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[Sol]

I should elaborate properly on the Canbus thing.

I've fitted LEDs to the sidelights and rear reversing lights and had to use so-called "Canbus" ones as the others tripped the bulb fail warnings. No idea why yours didn't show a burned bulb deejay. Try taking a good bulb out and check the diagnostics on the MFD display. It will tell you which one is bad. All lights are connected to the BSI which to be honest doesn't mean the lamps are actually "Canbus" but the BSI measures the resistance of the lamp is still there, so an LED doesn't show up, as it has no conventional measurable resistance. The so-called "Canbus" LEDs only have a resistor across them to simulate a standard filament lamp.

This is an immutable fact of physics and all cars that have blown bulb (lamp!) detection use the same system. In fact it's more likely at heart that the Canbus system is used to send a check pulse round the circuit to detect the lamp is good, rather than actually measuring the real resistance as that requires a Wheatstone bridge. If the pulse gets back, the lamp is intact. That requires a resistance value to be present. Once the BSI sees the pulse is returned, it powers the lamp and no warning is issued.

Sharpy, what are you connecting these LEDs to? The whole electrical system on the B9 shuts down to eco mode after 20 mins so nothing in the whole vehicle has power until the engine is restarted except the central locking, Including interior lights which turn themselves off at the same time.

Then once the engine is shut off, the countdown timer starts again. It can't be disabled either, only the time can be increased to 30 mins using DiagBox/Lexia.

[sharpy]

I’m trying to connect into wiring on the light in the back. Positive and negative. Although there is 3 wires. Put a light tester on it to see what one was live.


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[Sol]

Interior? Ok mate, it should work if the LEDs are 12v but once the eco timers expire the lights won't work until the next time you switch off and back on at the rear light controls or start the engine. Is this what's happening?

The reason for the three wires, one is ground, one is triggered by the door opening and one is triggered by the switch on the light so you can manually switch it on with the door shut. Still obeys the timers tho.

[sharpy]

Yea it’s not working not tried re starting to see if it re sets.

What would you suggest the best connections to splice wires in for lights?


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[Gryffindor]

If you have a lighter socket in the back for powering tablets etc then plug the lights into the wires in the back of that socket. They will need their own switch of course. If you can run cable from the lighter socket on the dash, then you can mount the switch somewhere there too.

But as Zion says, they will cut out on the timer. One way to avoid that is to have a small dedicated leisure battery and charging circuit to avoid flattening the main batt, though for just LED strips it only needs to be tiny. Maybe you could cannibalise the works in a rechargeable workshop torch if it can be charged from a 12v supply.

[Sol]

The best connection is to solder and heat shrink the joint. Failing that, make a twisted pair and use a butt crimp or male & female bullet crimps.