A device can be used for detecting failures in an illumination device having a plurality of light emitting diodes connected in series. A first circuit node, a second circuit node, and a third circuit node interface the illumination device such that a voltage supplying the plurality of light emitting diodes is applied between the first and the second circuit node and a first fraction of the supply voltage drop is provided between the third and the second circuit node. An evaluation unit is coupled to the first circuit node, the second circuit node, and the third circuit node and configured to assess whether a voltage present at the third circuit node is within a pre-defined range of tolerance about a nominal value that is defined as a second fraction of the supply voltage present between the first and the second circuit node.