Dial illumination

infinite · Nov 14th, 2007, 20:26

Not sure whats going on here but one of the rear panel bulbs on the right of the speedo is intermittently going off,dull or on. I suspected a faulty bulb but then it comes back again just as bright. Is this more than likely a general electrical fault or specific to that bulb/circuit? Thanks.

Clan · Nov 14th, 2007, 20:32

That will be the bulb , change all of the illumination bulbs at the same time in the instrument panel whilst it is out ...

milster · Nov 15th, 2007, 11:28

Quote:

Originally Posted by Clan

That will be the bulb , change all of the illumination bulbs at the same time in the instrument panel whilst it is out ...

Shouldn't the bulb just blow? I am having same problem, with the same bulb by the sounds of it to.

capt jack · Nov 15th, 2007, 11:48

Not necessarily. In true Hollywood fashion, bulbs can linger before they die! Sometimes you can get a bit more life out of a dodgy bulb just be giving it a whack. The filament is disintegrating, but you can temporarily 'repair' a complete break by shaking the bulb until the broken ends of filament weld themselves together. But it's only temporary - in technical terms that bulb is knackered!

In a dash it's a good idea to change all the bulbs together. They're a sod to get to, and given they've all done the same service, if one goes the others won't be far behind. Especially true in a Volvo with daytime running lights on all the time.

Jack

infinite · Nov 15th, 2007, 21:52

The whole thing makes sense logically but it was bugging me all the same. Thanks for the replies. I will just change all of them and worry about something else instead. Cheers!

homer timpson · Nov 27th, 2007, 12:10

Quote:

Originally Posted by capt jack

Not necessarily. In true Hollywood fashion, bulbs can linger before they die!.
Jack

I must have the Ronald Reagan version, because it's being dying on its feet for the past 2 years

Started way back in Winter 2005 - part of speedo and fuel guage would not illuminate for 1st 2 or 3 minutes of warm up - then all would be fine.

Problem went away for a month or two and then returned - this time they would stay out for 8 or 9 miles of driving [often they would come back on just as I was driving through the Clyde Tunnel each morning].

Now it is a bit of a wait and see when it comes on - anything between 10 & 25 minutes.

Maybe one day it will eventually make it all the way up to Boot Hill

Homer

hansol · Nov 27th, 2007, 13:16

I've got the same thing on my 99 V40 D. I thought it was a bad bulb at first so changed them all to no avail. It wouldn't bother me so much if I could turn the dash lights off during the day but even with the DRL's turned off they stay on.

matt123 · Mar 19th, 2009, 12:55

i have the same issue with the same fuel guage bulb very, did anyone get to the bottom of this? bulb or wiring fault?

M

rippedoffagain · Mar 20th, 2009, 17:40

On my 940 (I presume they all have something similar) there is a sliding potentiometer on the dash that controls the brightness of the bulbs iluminating the instrument cluster. If it is randomly changing brightness, I would suspect the potentiometer's contacts are dirty. Maplin used to do a really good aerosol contact cleaner for this very purpose.

I haven't bought any for years so I don't know if the stuff you get now is the same, the procedure is a simple one as follows:
*With the straw stuck in the nozzle (like you do with WD40), spray the contact cleaner right into the switch/potentiometer slider at point blank range. Just long enough to ensure that the whole switch has been covered in the stuff.
*Wait for about 30 seconds to allow the frost that forms on the contacts to thaw.
*Slide the slider/switch the switch, fully in each direction a few times.

It used to work wonders on the likes of volume controls on old hi-fis, I'm pretty sure it will be fine to use in cars too.

Don't use WD40 for this purpose. It will make matters 10 times worse, leave lots of stains, and smell. Contact cleaner is alcohol based and evaporates very quickly leaving no residue. As it is about 100% pure alcohol, it is very, very flamable, so don't be smoking while you use it.

S40D Sport · Mar 21st, 2009, 14:17

I have the same prob with my '01 S40 - are the bulbs hard to replace? What about the ones behind the heating controls? Any guides?

Nov 14th, 2007, 20:26	#1
infinite Junior Member Last Online: Jan 5th, 2009 23:00 Join Date: Jun 2007 Location: Doncaster	Dial illumination Not sure whats going on here but one of the rear panel bulbs on the right of the speedo is intermittently going off,dull or on. I suspected a faulty bulb but then it comes back again just as bright. Is this more than likely a general electrical fault or specific to that bulb/circuit? Thanks.

Nov 14th, 2007, 20:32	#2
Clan Experienced Member Last Online: Today 23:24 Join Date: Jun 2007 Location: L/H side	That will be the bulb , change all of the illumination bulbs at the same time in the instrument panel whilst it is out ... __________________ My comments are only based on my opinions and vast experience .

Nov 15th, 2007, 11:48	#4
capt jack VOC Member Last Online: Yesterday 00:31 Join Date: Jun 2006 Location: Selby, North Yorkshire	Not necessarily. In true Hollywood fashion, bulbs can linger before they die! Sometimes you can get a bit more life out of a dodgy bulb just be giving it a whack. The filament is disintegrating, but you can temporarily 'repair' a complete break by shaking the bulb until the broken ends of filament weld themselves together. But it's only temporary - in technical terms that bulb is knackered! In a dash it's a good idea to change all the bulbs together. They're a sod to get to, and given they've all done the same service, if one goes the others won't be far behind. Especially true in a Volvo with daytime running lights on all the time. Jack

Nov 15th, 2007, 21:52	#5
infinite Junior Member Last Online: Jan 5th, 2009 23:00 Join Date: Jun 2007 Location: Doncaster	The whole thing makes sense logically but it was bugging me all the same. Thanks for the replies. I will just change all of them and worry about something else instead. Cheers!

Nov 27th, 2007, 13:16	#7
hansol Junior Member Last Online: Oct 12th, 2010 22:20 Join Date: Jun 2007 Location: london	I've got the same thing on my 99 V40 D. I thought it was a bad bulb at first so changed them all to no avail. It wouldn't bother me so much if I could turn the dash lights off during the day but even with the DRL's turned off they stay on.

Mar 19th, 2009, 12:55	#8
matt123 New Member Last Online: Aug 6th, 2009 16:27 Join Date: Feb 2009 Location: surrey	i have the same issue with the same fuel guage bulb very, did anyone get to the bottom of this? bulb or wiring fault? M

Mar 20th, 2009, 17:40	#9
rippedoffagain Premier Member Last Online: Nov 16th, 2019 18:20 Join Date: Mar 2009 Location: Yorkshire	On my 940 (I presume they all have something similar) there is a sliding potentiometer on the dash that controls the brightness of the bulbs iluminating the instrument cluster. If it is randomly changing brightness, I would suspect the potentiometer's contacts are dirty. Maplin used to do a really good aerosol contact cleaner for this very purpose. I haven't bought any for years so I don't know if the stuff you get now is the same, the procedure is a simple one as follows: With the straw stuck in the nozzle (like you do with WD40), spray the contact cleaner right into the switch/potentiometer slider at point blank range. Just long enough to ensure that the whole switch has been covered in the stuff. Wait for about 30 seconds to allow the frost that forms on the contacts to thaw. *Slide the slider/switch the switch, fully in each direction a few times. It used to work wonders on the likes of volume controls on old hi-fis, I'm pretty sure it will be fine to use in cars too. Don't use WD40 for this purpose. It will make matters 10 times worse, leave lots of stains, and smell. Contact cleaner is alcohol based and evaporates very quickly leaving no residue. As it is about 100% pure alcohol, it is very, very flamable, so don't be smoking while you use it.

Mar 21st, 2009, 14:17	#10
S40D Sport Member Last Online: Jul 3rd, 2023 14:43 Join Date: Mar 2009 Location: Lisburn	I have the same prob with my '01 S40 - are the bulbs hard to replace? What about the ones behind the heating controls? Any guides?

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