W124 dash bulb not working

[sub_zero]

Hi to all members,
My W124 dashlight is so dim,I managed to reach the two main bulbs,they were too faded and old(but working!!!).
I decided to replace them with LED bulbs,installed new LED bulbs,nothing worked!!.
I switched polarity as I know LED bulbs have certain polarity,but still nothing works!!! I put again the old bulbs..and they are not working either!!!!
where I went wrong? I rotated the the bulbs holder around for 360 degrees with no lights on!!!!
Hope I wrote up in an understood English.
thanks in advance

 

[sub_zero]

Here are the two bulbs I replaced.
As you can see,the bulbs holder can be rotated,I rotated them for 360 degrees ,still nothing works

 

[llewe]

Sorry if this is too obvious but have you got the instrument panel rheostat turned up fully? LEDs probably wont work unless fed with very near full voltage

 

[sub_zero]

After replacing the bulb,I turned the rheostat up and down for both.
Now the original bulbs are not working too

 

[llewe]

All my dash lights failed suddenly a couple of months ago- it was a break in a solder joint in the printed circuit board which was re-soldered (I didn't do it so unfortunately I cant tell you where exactly) so all I can suggest is test the continuity with a meter