Got it - I thought you had tried to plug an ice cube relay into the physical space occupied by the KLIMA relay. When you say "I replaced the KLIMA relay with an ice cube relay" I suspect I was not the only one that had assumed this.....

If you are losing the ground signal to trip the relay it should not be too hard to figure out if you are losing the signal via the CCU or one of the switches that will interput the ground signal.