Intermittent power 3rd brake light W210 1997 E420

[bpollard]

I replaced the light bulb. still did not work.
Had my wife step on the brake, and eventually the light would turn on, and when it came on it stayed on good.
she would let off the brake, then press it again, and no power to the bulb. I woudl fiddle with the connectors (pushing down on them hard, etc), and the light would come back on.

Since the bulb eventually gets power, can I rule out the fuses?
The connections seem very solid, no corrossion or anything. what is my next step? is there some way to pop off that whole assembly and see where the wires connect from the underside? I looked in the trunk and there didn't seem any easy to way to do that.
Suggestions are greatly appreciated.
thanks!

[Steve M]

If you replaced the bulb, you must have removed that plastic cover by pushing in on both sides, and sliding it toward the front of the car, right? Referring back to my Alldata instructions,:to remove the rest of the thing, you push up on a single retaining tab that is underneath, while simultaneously pulling the assembly (gasket and all) away from the window. You have to line up guides on each side to reinstall.

I did this last year on my E420 just so that I could clean the window and the gasket, which had a white-ish look to it. I recall that it took me a long time to figure out how to do it, even with that tidbit of knowledge about the retaining tab that I just shared with you.

I don't know if this will help you track down your problem or not, but Good Luck.

[bpollard]

My independent mechanic just told me that this assembly will melt from the heat (the aluminum) and to get a new assembly. I was also having intermittment problems. I have not got a new assembly yet.

Originally Posted by bpollard

I replaced the light bulb. still did not work.
Had my wife step on the brake, and eventually the light would turn on, and when it came on it stayed on good.
she would let off the brake, then press it again, and no power to the bulb. I woudl fiddle with the connectors (pushing down on them hard, etc), and the light would come back on.

Since the bulb eventually gets power, can I rule out the fuses?
The connections seem very solid, no corrossion or anything. what is my next step? is there some way to pop off that whole assembly and see where the wires connect from the underside? I looked in the trunk and there didn't seem any easy to way to do that.
Suggestions are greatly appreciated.
thanks!

[nelbur]

Originally Posted by bpollard

My independent mechanic just told me that this assembly will melt from the heat (the aluminum) and to get a new assembly. I was also having intermittment problems. I have not got a new assembly yet.

The '97 E class has a problem where the light assembly presses on the plate like electrical contacts on the package shelf. The assembly's spring type contact will overheat and melt the plastic under the plate like contacts, which will sink into the package shelf a bit. I doubt that a new assembly will be a permanent solution but it might be. I cleaned the spring contact and put a blob of solder on it so it would again press firmly on the recessed plate contact. I have about 5 years on the repair.

[bpollard]

If I buy this part off ebay (does Peach Parts sell it?) do you think that it contains all of the electrical parts that are in question/problem? Look at the second picture on eBay (shows the underside of the brake light assembly).
thanks!
http://www.ebay.com/itm/Genuine-OEM-Mercedes-E320-E430-w210-Third-Brake-Light-Brake-Lamp-96-99-/281090345905

Originally Posted by nelbur

The '97 E class has a problem where the light assembly presses on the plate like electrical contacts on the package shelf. The assembly's spring type contact will overheat and melt the plastic under the plate like contacts, which will sink into the package shelf a bit. I doubt that a new assembly will be a permanent solution but it might be. I cleaned the spring contact and put a blob of solder on it so it would again press firmly on the recessed plate contact. I have about 5 years on the repair.

[jay_bob]

The rear lights (both the 3rd brake light as well as the tail lights) on the W210s were not the best designs.

I think someone at M-B was trying to impress their boss with the fancy CAD/CAM systems just coming online in the early 90s. Great concept but poorly executed.

It appears to me that the 210 was the first car where they CAD modeled the entire car and then CNC cut the molds for the plastics from the CAD files.