W124 94 E320 - Rear defroster not functioning

[chinny4290]

Hey guys. I need some help.

For some reason my rear defroster will not stay on. I can push the button, and the yellow LED turns on, but only stays on if I hold it. In no other fashion will it stay on unless I hold the switch in the on position.

It worked a while ago...when I mean a while ago I mean last winter...but stopped working since then.

Anyone have any advice on this?

Thanks guys,

[babymog]

Convenience module.

Behind the fusebox, there is a lid held by four screws. Remove that and the long relay-looking module in the center is the "convenience module". This controls the latching function and timing of your rear defogger (among other things), you're experiencing a common failure mode of this module.