'Bulb out' warning light, but no bulbs faulty

david75 · 26th October 2016, 21:34

As per title, my 'bulb out' warning light is on, but all my lights seem to be working ok.

It also came on a few weeks ago and I needed to replace a brake light bulb, and then the warning light went off ok. But it came on again today for no apparent reason.

Any suggestions? Thanks

stevestrat · 26th October 2016, 21:45

Check the number plate lights and tail lights. If a tail light fails the brake light on that side will come on dim to compensate.

SCP440 · 27th October 2016, 07:06

Also worth checking the bulb holder and even if the bulb has started dimming, any resistance change and you will get the warning. I had a car last year I was working on and in the end all the side light bulbs were replaced to stop it coming on even though they were all working.

Darcydog · 27th October 2016, 07:49

I have an odd thing that has happened twice now on my Tourer - the bulb warning light came on and I looked round and at first I thought all lights were operating OK

But then I noticed that the the Rear Offside light was the very top section of the light cluster and the Rear Nearside light was the central section.

I also noticed that the Offside rear cluster was not sitting properly and so gave it a palm slap to put it in line which it did no problem and this also cured the odd light configuration with the top section going out and the middle section coming on - and the dash warning light going out

It happened again and the cure was the same - a mild thump on the light cluster and all is well again. Since making sure the light is sitting right I have had no more problems - so far.........

hogweed · 27th October 2016, 08:36

Quote:

Originally Posted by SCP440

Also worth checking the bulb holder and even if the bulb has started dimming, any resistance change and you will get the warning. I had a car last year I was working on and in the end all the side light bulbs were replaced to stop it coming on even though they were all working.

This is true. Take all bulbs out, sand both the ends of the bulbs and the little spring "tang" they contact with, and apply a dab of vaseline or similar.

Also replace any bulbs which look a bit black inside, even if they seem to be working perfectly.

And check your numberplate lights...

stevestrat · 27th October 2016, 08:48

Quote:

Originally Posted by Darcydog

I have an odd thing that has happened twice now on my Tourer - the bulb warning light came on and I looked round and at first I thought all lights were operating OK

But then I noticed that the the Rear Offside light was the very top section of the light cluster and the Rear Nearside light was the central section.

I also noticed that the Offside rear cluster was not sitting properly and so gave it a palm slap to put it in line which it did no problem and this also cured the odd light configuration with the top section going out and the middle section coming on - and the dash warning light going out

It happened again and the cure was the same - a mild thump on the light cluster and all is well again. Since making sure the light is sitting right I have had no more problems - so far.........

You have a dodgy connection on the offside tail light, when it goes out the brake light is coming on to compensate. Its a safety feature that catches a lot of people out when trying to find a light out, including me when I first bought a 75. Take the tail light bulb out and clean the contacts on the bulb and holder.

T-Cut · 27th October 2016, 10:05

Quote:

Originally Posted by SCP440

I had a car last year I was working on and in the end all the side light bulbs were replaced to stop it coming on even though they were all working.

The CANbus bulb testing system on 'modern' cars can differentiate between say a 5watt bulb and 10watt bulb. The 75/ZT doesn't have that sensitivity, so almost any resistance will satisfy the test. It doen't have to be the Ohm's Law figure for each particular bulb.

TC

TomRS · 27th October 2016, 13:43

Quote:

Originally Posted by stevestrat

You have a dodgy connection on the offside tail light, when it goes out the brake light is coming on to compensate. Its a safety feature that catches a lot of people out when trying to find a light out, including me when I first bought a 75. Take the tail light bulb out and clean the contacts on the bulb and holder.

This is a BMW thing, same thing happens if you lose a sidelight on a beemer the indicator comes on dim to compensate, same with the tail lights/brake lights.

david75 · 18th November 2016, 18:14

Finally got around to having a closer look at the problem I described in the original post, an discovered that ... the bulb had fallen out ! The intermittentness must have been because I didn't seat/twist the bulb correctly so it eventually dropped out. Anyway all sorted now. Thanks for all the comments.

planenut · 18th October 2023, 06:46

Thanks for letting us know, well done with your search. The advice on cleaning the connectors is very well worth noting for us all.

26th October 2016, 21:34	#1
david75 Posted a thing or two Rover 75 2.5 V6 Conn SE, 04 Join Date: Sep 2012 Location: Southend Posts: 1,176 Thanks: 544 Thanked 302 Times in 165 Posts	'Bulb out' warning light, but no bulbs faulty As per title, my 'bulb out' warning light is on, but all my lights seem to be working ok. It also came on a few weeks ago and I needed to replace a brake light bulb, and then the warning light went off ok. But it came on again today for no apparent reason. Any suggestions? Thanks __________________

26th October 2016, 21:45	#2
stevestrat This is my second home ZT260 #243 (resting) Join Date: May 2010 Location: Prestonpans Posts: 22,555 Thanks: 650 Thanked 4,624 Times in 3,358 Posts	Check the number plate lights and tail lights. If a tail light fails the brake light on that side will come on dim to compensate. __________________ Steve T4 Location Map

18th November 2016, 18:14	#9
david75 Posted a thing or two Rover 75 2.5 V6 Conn SE, 04 Join Date: Sep 2012 Location: Southend Posts: 1,176 Thanks: 544 Thanked 302 Times in 165 Posts	Finally got around to having a closer look at the problem I described in the original post, an discovered that ... the bulb had fallen out ! The intermittentness must have been because I didn't seat/twist the bulb correctly so it eventually dropped out. Anyway all sorted now. Thanks for all the comments. __________________

27th October 2016, 07:06	#3
SCP440 I really should get out more....... MG ZT-T 260 Join Date: Feb 2016 Location: Witney Posts: 2,508 Thanks: 6 Thanked 910 Times in 571 Posts	Also worth checking the bulb holder and even if the bulb has started dimming, any resistance change and you will get the warning. I had a car last year I was working on and in the end all the side light bulbs were replaced to stop it coming on even though they were all working.

27th October 2016, 07:49	#4
Darcydog This is my second home Join Date: Jul 2014 Posts: 5,428 Thanks: 3,123 Thanked 3,170 Times in 2,096 Posts	I have an odd thing that has happened twice now on my Tourer - the bulb warning light came on and I looked round and at first I thought all lights were operating OK But then I noticed that the the Rear Offside light was the very top section of the light cluster and the Rear Nearside light was the central section. I also noticed that the Offside rear cluster was not sitting properly and so gave it a palm slap to put it in line which it did no problem and this also cured the odd light configuration with the top section going out and the middle section coming on - and the dash warning light going out It happened again and the cure was the same - a mild thump on the light cluster and all is well again. Since making sure the light is sitting right I have had no more problems - so far.........

18th October 2023, 06:46	#10
planenut Regional Secretary Rover 1.8T Tourer Join Date: May 2007 Location: Heathrow Posts: 6,998 Thanks: 1,551 Thanked 2,036 Times in 1,264 Posts	Thanks for letting us know, well done with your search. The advice on cleaning the connectors is very well worth noting for us all.