Dome light trouble shooting?

Mickyfin

Member
Hmm - that's frustrating.

Do you have access to another dome light which you know is working (or another Sprinter / Crafter you can try installing your dome light into)?

That would confirm if the fault is in the dome light itself or in the connection to it.

I would offer to post you mine - but I suspect the postage costs to send it to Finland and back to the UK would make it impractical.
Its a brand-new OEM light mate, purchased it in the hope it would work correct, but it does exactly the same as it did with the original one.

Spray a healthy dose of wd40 into the driver side lock and then use compressed air to blow it all out. That makes the door sensor work sometimes
I will go and try this right now on both front doors, I have both on hand, compressed air, and WD, so will report back.
 

Mickyfin

Member
Well I tried the WD, and compressed air, but no dice.

Incidentally, and I'm not sure if this is the same with all Sprinters and VW Crafters? but when the van is locked, and I use the actual physical key to open the drivers door, (only front door with a keyhole), the only door that unlocks is the drivers door, the passenger door remains unlocked, same when locking the drivers door with the actual key, it only locks the drivers door, and not the passenger door.
 

sparkplug

Active member
Well I tried the WD, and compressed air, but no dice.

Incidentally, and I'm not sure if this is the same with all Sprinters and VW Crafters? but when the van is locked, and I use the actual physical key to open the drivers door, (only front door with a keyhole), the only door that unlocks is the drivers door, the passenger door remains unlocked, same when locking the drivers door with the actual key, it only locks the drivers door, and not the passenger door.
Yes - that's the same as mine. Manual key only operates the driver's door for lock and unlock.

No other doors affected.
 

Mickyfin

Member
OK, so now I guess I need to see if its possible to reset the SAM/CBM via the OBDII, anyone know if it's possible? I want to avoid taking the van to the dealer for something so small, but it is doing my head in, and would like to sort it out myself.
 

Mickyfin

Member
Just been back out to the van to check over everything, and going back to an earlier question based on me reading elsewhere that the cigarette lighter illumination, and that if this bulb has blown, it could be the cause for the dome light not coming on when the two front doors are opened, or switching the dome light on when remotely opening the doors, and when removing the key from the ignition.

Now having checked the cigarette light illumination in my van, it's not working, so we could be onto something, however, how on earth does one go about replacing this bulb in the cigarette lighter?

I've tried pulling on it, but its clipped in.
 

Mickyfin

Member
Ok, a search found this..
Finally got it.

There are no screws, only hidden tabs that need to pressed from their normal position to allow removal of both parts of the ashtray assembly i.e. the ashtray carrier and the ashtray itself. Remove the entire assembly first, then remove the ashtray from the ashtray carrier. I used a stout trim tab tool to do both, but an appropriately sized screwdriver should work if one is careful and has lots of patience. Be careful not to loose two tiny springy things that will come out when you remove the ashtray from it's carrier.

These photos should help others.

http://i1283.photobucket.com/albums/a551/digittalguy/Ashtray1with text_zpspdekxp8p.jpg

http://i1283.photobucket.com/albums/a551/digittalguy/Ashtray2with text_zpseqgwooua.jpg

View attachment 66979

View attachment 66980

Please advise if some other "URL" format is needed to see the above photos on photo-bucket.
 

Mickyfin

Member
Successfully removed the ashtray and housing by using a pair of body trim removal tools. I was struggling with two small metal rulers, and turned out they were too thin to release the ashtray.

The lighter illumination bulb is clearly blown, so finding one of these shouldn't be too taxing, however, removing the bulb holder from the lighter socket itself, I broken a tiny clip off the bulb holder, so need to find a replacement, part number is Valeo 73947081

Probably cheaper to buy a replacement ashtray second hand.
 

sparkplug

Active member
I was looking at them - they're around 135 FIM on eBay.

The reason I was looking was because I was considering removing mine completely and building a small centre console to act as a cup holder / storage and putting a second small storage tray place of the cup-holder / ashtray / cigarette lighter. I'm actually surprised that I haven't seen anything like this for sale as an aftermarket part. The only things I've seen are big boxes which sit between the driver / passenger seats and block the walkway through to the back.

I'd run the cabling for the lighter socket up through the dash and mount it somewhere more useable at the top of the dash so I don't have charging cables trailing up past all the controls (very bad design IMO)
 

Mickyfin

Member
Update, ash tray bulb renewed, and working, however, my dome light still isn't switched on when either of the front doors are opened :(
 

Mickyfin

Member
Further update to the above update, I had fit an red led in there, so thought I would try a new normal old school bulb to see if the dome light would come on when doors opened, but alas I'm afraid not :(

Surely this can't be a main dealer thing to reset only?
 

Mickyfin

Member
Still scratching my head with this issue, anyone also to assist?
 

brassmonkey001

UK 2008 NCV3 518 CDI
Mine doesn't work either. I'm glad you ruled out the ashtray light as the cause because mine doesn't have an ashtray so that would make it even more difficult for me!
Also, the light in the glove box doesn't work either, I don't know if there's a connection there?
 

Gabe Athouse

New member
Funny how the simplest thing can cause so much frustration. I’m also having a similar issue, and haven’t really examined it yet except to notice door switch is somehow harder to find than any other car I’ve owned.
 

sparkplug

Active member
That's because the door switch is integrated in the locking mechanism (it took me WEEKS to figure that out)

It's a really fiddly job to replace the mechanism and not one which seems to be well documented on the internet.

I think that's probably because you would need to be an octopus to remove and re-fit one and still take pictures or video of it!

Swapping that out fixed the problem for me - I just wish I'd documented it more carefully. For example, I don't know if the 'door open' light showed on the dash before I fitted the new one.

Note that there are two positions on the door latch. There's a door open and a door ajar setting. You can easily feel the two positions if you open the door and manually click the lock with a screwdriver. Some people report the lights working on one setting but not the other.

First thing to check though (at least with the four button version of the dome light) is that you haven't got the light turned off with the buttons....

Also worth checking other obvious things like the bulbs are working...
 

Say what

New member
Not on topic but I swapped out to LED lights for all the domes and now the faintly glow even with doors closed when on auto position. The higher draw original bulbs never did this, but the LED seem to be getting a trickle current from somewhere.
 

elemental

Dis member
Not on topic but I swapped out to LED lights for all the domes and now the faintly glow even with doors closed when on auto position. The higher draw original bulbs never did this, but the LED seem to be getting a trickle current from somewhere.
The module that monitors for problems with the electrical system trickles current through the lights so that it can detect circuit failures/bulb failures. Higher resistance incandescent bulbs don't light up with the small amount of current, but LED bulbs do. Some people have reported good results from putting a resistor in series with the LED bulbs. I decided I would just stick to the incandescents. Whether this is an example of MB overthinking is a matter of opinion.
 

Gabe Athouse

New member
The module that monitors for problems with the electrical system trickles current through the lights so that it can detect circuit failures/bulb failures. Higher resistance incandescent bulbs don't light up with the small amount of current, but LED bulbs do. Some people have reported good results from putting a resistor in series with the LED bulbs. I decided I would just stick to the incandescents. Whether this is an example of MB overthinking is a matter of opinion.
I’d certainly say it’s over thinking because it sure is wasted electric and will lead to a dead van in no time which is a very common problem. Don’t waste energy MB!
 

sparkplug

Active member
Yes - I fixed mine by simply replacing the door lock mechanism as the issue was to do with the door open/ajar sensor not working not the dome itself.

If you know someone else with a known working dome who is prepared to let you spend ten minutes testing your dome in their van you can help narrow the problem down.
 

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