CLK 1999 aircon control lights

I had this same problem. I removed the aircon controller from the dash and found two dry solder joints on the back of the main circuit board. I resoldered these and it fixed the problem.

YOU PROBABLY HAVE A HARD CODE STORED IN THE CONTROL UNIT.YOU MAY BE ABLE TO ERASE IT BY DISCONNECTING THE BATTERY FOR A FEW MINUTES.IF NOT YOU WILL HAVE TO HAVE VISIT A DEALERSHIP TO HAVE IT CHECKED.

hi there are small bulbs behind the display, similar problems happen sometimes with the dash lights too, can be fixed fairly easy just by removing unit and replacing bulbs brought from the local auto dealer or parts shop

where did u install the FOG LAMP relay and what connection of power( + ) did u connected it to? If the Lamp u have use is more 100 watts, u have to get the power directly to the battery and make power line independent from other accessories!
Try it! Taaah!

Yes they should light up at night, the source of the problem is either the tiny miniature bulbs are burned out or the Rotating contact ribbon (known as the Clock Spring) under the steering wheel is defective and the lights are not getting any power.

the bulbs are made into the a/c control head and are not replaceable. the only way to get them working again is to replace the hole assembly.

this is most often caused by a slightly low charge of refridgerent, as the engine heats the system the gas expands and the light goes out.

the light should be on when air con is working. only works when the blower is on ,ie heater blower switch on=air con light lit up = aircon working.

The econ button allows you to set the heating manually, With this button pressed only manual heating is on and aircon is off.if you want heating and aircon off press the OFFbutton

Apparently, this problem you are experiencing is quite common in VW MK4 Golfs, it's not the bulb but the lighting connection behind your switch. If you bang the right hand side sides your gan controls your fan lights should appear again. Sounds crazy but it's true. I know few people with VW Golf who have this problem.