w123/126 instrument lighting - PeachParts Mercedes-Benz Forum

hangit · #1 12-10-2007, 11:17 AM

Several threads have mentioned cleaning/painting/lining the light tunnel and prism to improve brightness. Are these components removable from the instrument panel or are they cleaned on the cluster? Thanks for any advice.

John

toomany MBZ · #2 12-10-2007, 04:54 PM

Once the cluster is removed, silver tape on top of the "tunnels".

hangit · #3 12-10-2007, 06:11 PM

Quote:

Originally Posted by toomany MBZ

Once the cluster is removed, silver tape on top of the "tunnels".

I'll give it a try. I had no dash illumination so I replaced the stock bulbs with LED's, but the only difference I noticed is the turn signal indicators are now constantly lit (they do flash when stalk lever is flipped and dim with the rheostat).

Any ideas?

John

toomany MBZ · #4 12-10-2007, 07:02 PM

Quote:

Originally Posted by hangit

I'll give it a try. I had no dash illumination so I replaced the stock bulbs with LED's, but the only difference I noticed is the turn signal indicators are now constantly lit (they do flash when stalk lever is flipped and dim with the rheostat).

Any ideas?

John

Sounds like a plug or two have been reversed.
The pics show a 123 and a 126 cluster, the latter has white tunnel covers, for lack of a better term.
In the second pic, near top, the larger bulb backs are the cluster lights, there is only one way, I think to plug in the multi pronged plug, so can't figure out why they are reversed.

daw_two · #5 12-10-2007, 09:46 PM

the LEDs were so bright that the light was "bleeding" over into the turn signal area....causing the turn signal to be dimly lit all the time.

By the way, does the silver tape really work? When I pulled my instrument cluster, I spray painted the litle cavity white. Helped some, but only the right bulb works........the left one must not be making good contact. One of the PO had put 5watt bulbs in there and had melted the plastic.

toomany MBZ · #6 12-11-2007, 06:41 AM

Quote:

Originally Posted by daw_two

the LEDs were so bright that the light was "bleeding" over into the turn signal area....causing the turn signal to be dimly lit all the time.

By the way, does the silver tape really work? When I pulled my instrument cluster, I spray painted the litle cavity white. Helped some, but only the right bulb works........the left one must not be making good contact. One of the PO had put 5watt bulbs in there and had melted the plastic.

Maybe, yet there are separation partitions.
I've heard, the tape thing helps.

hangit · #7 12-11-2007, 02:24 PM

I do think the light is bleeding over into the turn signals, not sure why. The larger cluster bulbs will not fit in the turn signal spot, so I know they are placed correctly. I'm not sure why I don't have any illumination down the tunnel. Where are people putting the reflective tape?

I'll pull the whole instrument panel this weekend and take a closer look a the illumination tunnel.

John

Chad300tdt · #8 12-11-2007, 03:24 PM

John,

The two bulbs that light the faces of the gauges through the light tunnels and prisms shouldn't be giving any bleed over light to the turn signals unless the tunnels and prisms got melted. I used to think that just making sure the correct bulbs were used would be fine. I now have experienced the temp wheel socket for my CCU getting a bit melted by a standard correct wattage bulb. I will now replace all the 2721 bulbs with 74 wedge base LEDs even though they are dimmer than stock bulbs. Cooler LEDs will preserve all the plastic parts surrounding them.

Here's a link about where to put the silver tape: Silver Taping the Tunnels

After taping the tunnels I noticed a brighter cluster even with the stock bulbs.

If your tunnels are melted, I think you could use a dremel and cut them out to glue replacements in from a donor or replace the whole thing. Maybe it's even easier than that. I haven't had my cluster apart, just out of the car, so I don't know how the tunnels and prisms are attached on the inside. It looked like a plastic weld or glue to me from what I could tell.

KAdams4458 · #9 12-11-2007, 03:38 PM

Quote:

Originally Posted by Chad300tdt

...The two bulbs that light the faces of the gauges through the light tunnels and prisms shouldn't be giving any bleed over light to the turn signals unless the tunnels and prisms got melted.

...If your tunnels are melted, I think you could use a dremel and cut them out to glue replacements in from a donor or replace the whole thing. Maybe it's even easier than that. I haven't had my cluster apart, just out of the car, so I don't know how the tunnels and prisms are attached on the inside. It looked like a plastic weld or glue to me from what I could tell.

Bingo, and bingo, at least in regard to W123 clusters. I butchered a couple of them to make one good one, and still had to wet sand and polish the clear bezel. On all of them, melted bezels always resulted in light bleed. A little creative epoxy work and reflective tape might solve that problem.

I personally use two cluster assemblies with one melted tunnel each to make a good one. A Dremel was used to remove material from the plastic spot welds to allow disassembly, and re-assembly was done by heat-fusing the plastic with a heated air torch. A soldering iron would also work, but may be messier. Epoxy, or even superglue could be used instead.

hangit · #10 12-11-2007, 06:47 PM

If the tunnels are melted, it would have been done by the previous owner. Currently the instruments are illuminated with stick on LED's on the front of the glass, with the power supplied at the cigarette lighter. Effective but not stock! I really would like to eliminate them, so this weekend I might attempt repairing the tunnels.

John

trogmaster · #11 12-27-2007, 06:42 PM

Quote:

Originally Posted by hangit

I'll give it a try. I had no dash illumination so I replaced the stock bulbs with LED's, but the only difference I noticed is the turn signal indicators are now constantly lit (they do flash when stalk lever is flipped and dim with the rheostat).

Any ideas?

John

U said that you replaces dash lts w/led. What bulb # did you use?

hangit · #12 12-27-2007, 10:04 PM

Quote:

Originally Posted by trogmaster

U said that you replaces dash lts w/led. What bulb # did you use?

HID white SMT 5 LED bulbs 45689. I found them on Ebay. Here's another link. http://www.ledlight.com/detail.aspx?ID=167.

I haven't tried repairing the light tunnels yet. Since the add ons are still working I'll wait till they quit.

John

hangit · #13 12-29-2007, 10:01 PM

I finally pulled the cluster today, lined the instrument light sockets with aluminum tape and plugged it in expecting bright panel lighting. Instead there is no power to the cluster lights, yet the turn signal indicators are lit and respond to the rheostat. If I remove the cluster lights from the sockets, the turn signal indicators act normally.

I have grounded the cluster to the back of the speedo. Could this be causing the problem or is it more likely a broken circuit?

John

zsmith29 · #14 12-30-2007, 12:04 AM

dangit,
My lights in my 300d do the same thing. I just put some tape over the turn signal indicator and decided to live w/ it