463 electronics and rear lights
Here's a weird one. And a good example of why old school don't like modern electronics and ECUs. My G350 reversing light fail warning came on. But it was working. Then the Tail light failure came on, but it was working, on and off. Right hand side only.
I decided to check and replace the bulbs, and found one tail light bulb burnt out. It's a small 12v 5w one, but the blown one was 12w. Replaced it... Still no tail light.
Suspected fuse, to find that all the rear lights are ECU controlled, not via fuse box. Indicator still working, so to test the other bulbs and earth's, I connect the indicator to the bulbs in turn. Immediately the brake light takes over flashing, like an indicator! Wth.
Turning ignition off and on does not reset it. Activating the brake does. It's repeatable. But still no tail light on that side. Brake, indicator, fine.
Now, the tail light is double bulbs. But there is no actual voltage to the light unit, the wire goes to the left hand bulb and is linked to the centre one (which is a double filament, with one for the brake and one for the tail light). If one bulb fails, the remaining bulb should still work, but If there is no voltage, neither will work obviously. It seems to be the ECU that controls the supply, so I look to resetting that ... Go to OBD adapter, check errors. No errors.
Notice that when side lights are first turned on, the light comes on for a second and goes off, then on and finally off again. Wth.
Note, this was a non OEM replacement light cluster (it came with bulbs in, and I suspect the 12w one was incorrect). So I put the old ones back on (so much better quality than the eBay knock-offs) - but no change.
Any ideas in the meantime? Is it worth just changing all the bulbs? Maybe the ecu is not liking the resistance of one of them.
Ed: maybe I have the tail and brake mixed up...need to check that.
Different beast, I know, but when I used to have a 300TE the warning light system didn't like it when I used anything but Bosch bulbs.
Put in a Lucas bulb and the bulb worked but the warning on the dash said it wasn.t.
Sounds like a bad earth
Sounds like a bad earth
Yes but no. The 463 has a single earth lead for all the rear lights, and the rest work fine.
Solution:
It turned out.... The non OEM replacement cluster had the centre bulb (dual filament, 21W brake and backup 5W tail light) in a different orientation (I think 180deg round) although they marked it up, so I had connected the primary tail light to the 21W brake bulb.
Once I switched those over, the tail light (2 x 5W) resumed correct operation. But the 21W brake filament now threw the error. I knew the bulb worked, but figured a different (Bosch) bulb would be worth trying (probably the non-OEM bulb was a cheapie, although it looked identical).
Sure enough, all now working again.
Moral of the story:
Beware of non-OEM light clusters. They are shiney and look the same, but the plastic quality is poor and even the mounting holes will crack when you screw them on.
ECU controlled lights can behave weirdly... the ECU protects itself and turns off power when it doesn't like something. Cheap bulbs can be a problem in themselves, and the ECU detects that and 'computer says no' happens.
You know I had this issue ! So mine are non OEM too and mine had no lights at all at the rear. Imagine that and I knew it was ECU controlled with Rear Sam unit. I ended up swapping out for a used one and presto had rear lights! The main issue i had after this was rear lights were small LED version with resistors attached to the back of them these were defective and were constantly shutting down the rear lights! After x3 times of depressing the brake pedal they would stop working. All other lights were fine but brake lights needed attention.
Yes for sure stick to the OEM type versions you'll have less headache
after removing the complete centre console i was able to replace rear sam wasnt that bad you need a good hour and half to take out and put new or replaced module in.
attaching rear sam pics
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Sounds like a bad earth
Yes but no. The 463 has a single earth lead for all the rear lights, and the rest work fine.
Solution:
It turned out.... The non OEM replacement cluster had the centre bulb (dual filament, 21W brake and backup 5W tail light) in a different orientation (I think 180deg round) although they marked it up, so I had connected the primary tail light to the 21W brake bulb.
Once I switched those over, the tail light (2 x 5W) resumed correct operation. But the 21W brake filament now threw the error. I knew the bulb worked, but figured a different (Bosch) bulb would be worth trying (probably the non-OEM bulb was a cheapie, although it looked identical).
Sure enough, all now working again.
Moral of the story:
Beware of non-OEM light clusters. They are shiney and look the same, but the plastic quality is poor and even the mounting holes will crack when you screw them on.
ECU controlled lights can behave weirdly... the ECU protects itself and turns off power when it doesn't like something. Cheap bulbs can be a problem in themselves, and the ECU detects that and 'computer says no' happens.