[Qmulus]

My guess is that there is a relay problem in the alarm/immo module, but this exact failure is not common. I would check to see if there was any apparent water intrusion in the alarm/immo module, but honestly if there is cleaning is likely not going to do much good. In my experience, most of the corrosion and damage is under the relays and you cannot get at it unless you remove them. Unless you have a lot of experience with that kind of work, I would not attempt to remove them, especially if there is a lot of corrosion as it is very easy to damage the relays and PCB needlessly. Usually the relays can all be salvaged, and the PCB repaired even with fairly extensive corrosion damage. That said, waiting for things to stop working before doing anything about it increases the likelihood that the module is not economically repairable.