Clock backlight on Dash is Intermittent - PeachParts Mercedes-Benz Forum

99clk320 · #1 04-20-2003, 10:32 PM

I've searched through past posts but can't find this exact problem.

The lighting on the clock of my 99clk320 has gone out. The speedometor, temperature gauge and everything else is fine. What's more, it seems that ever few days, the light comes back on! I just bought the car used and found out that the car has been in an accident before. Is this just a fuse or a bulb that I need to replace?,... or am I in store for a lot more electrical problems?! (i have no warranty of course)

Thanks to all the MB pros for your help.

G-Benz · #2 04-21-2003, 12:32 PM

Probably just a bulb on its way out. There are two (or three) that handle dash illumination, so the absence of one bulb will darken at least one of the gauges in the cluster.

You can verify bulb operation by rapping against the dash near the cluster...if the clock illumination returns, a bad bulb is the suspect.

The bulbs are 2W units. These are a bit difficult to find at auto parts stores, but the dealer should have them for around $4-$6.

The gauge cluster must be removed from the dash in order to gain access to the bulbs.

I don't know if you can just pull the cluster out, as you have a 99. My 93 300E and 95 SL500 clusters just pull out (snug fit), but my 99 ML320 cluster is bolted to the dash.

99clk320 · #3 04-21-2003, 09:04 PM

G-Benz, thank you so much for taking your time out and helping me. Its a great relief to know that you think its just a bulb and not the start of some major electrical problems. I'll try tapping on the glass and will buy some bulbs online.

I've read in so many places about how easy it is to take off the dash, even without the dash hook tool. What I've also read is that getting the thing out isn't the hard part, its trying to put it back without cracking the clear plastic casing that's difficult.

Oh well,... wish me luck. Thank you again!

joe p · #4 04-22-2003, 07:36 AM

pop the cluster and replace the 3 tan base 2v 1.5w bulbs in the lower center section. nothing unsual there.

Joe

G-Benz · #5 04-22-2003, 01:07 PM

Joe is correct. I forget, the earlier MBs have the big analog clocks that are backlit with the 2W bulbs that illuminate the other gauges. The digital clocks (like in my ML) use the 1.2W (or 1.5W bulbs) that are also used for all the warning indicators.

99clk320 · #6 04-23-2003, 12:30 AM

Thank you both for your help. I also found the following post which helps with the dash removal, albeit I don't know if this same procedure works with newer MB models (e.g. my 99clk)
How to remove instrument cluster.

I know this topic has been posted a thousand times on this board, but... to be a single source of info, can anyone clarify?...

some posts say that after acquiring the hook tools, you still have to do certain things before effectively being able to change your bulbs:

including the following:
- disconnect the battery
- disconnect your speedometer cable in multiple places?
- remove some bolts or other wires?

Can anyone clarify on the steps prior to pulling the dash out?

Thanks again!

blackmercedes · #7 04-23-2003, 09:02 AM

Don't bother disconnecting the battery. You'll then need to code the radio, etc. You could pop the fuses for the instrument panel.

Your car has no speedo cable.

Your cluster has no "wires" to be disconnected. It's molex plugs that pop out when you pull the cluster.

Buy the tools, pop the cluster, replace ALL the bulbs (why go back in soon?) and push it back in.

99clk320 · #8 04-24-2003, 08:40 AM

Strange... is it really the bulb though?
I've been taking a look on this other thread
Outside Tempature Gauge Illumination on dashboard...
and it seems as if some folks went through the entire bulb swap process only to find that that really isn't the problem.

I find it very strange on mine because it's not as if the lights are dimming or anything. The backlight is either completely out, or it's on and as bright as it ever was.
When I was taking a look at it yesterday night to figure out how what I was in for as far as removing the dash, the backlight behind the click mysteriously came back again.

I'm expecting it to go out anytime now... (this happened twice before)

If its a bulb, shouldn't it go OUT and that's it? It can't be a fuse otherwise the entire dash would be dark, right?

Very strange...

blackmercedes · #9 04-24-2003, 10:02 AM

This happened to my C230. The clock light would go on and off. It never dimmed, but would "mysteriously" come back on.

I change the bulbs, and problem solved. The symptoms you describe might not be the bulb, but they do match a bulb failure (failing) as well.