MUC089, note I never said (and I don't think neither) that "the engineer should have known that the TOWS could be affected too".
I think that just taking on the problem with an "electrical mindset" would have guaranteed focus to be about the power circuit and not the RAT heater itself, even without knowing or remembering about the relation with TOWS, it would have been enough.
Note I say that having the most respect toward Engineers category (I'm one, but in a different industry) and with the most compassion for specific individual involved.
From the preliminary report I see that he may have been present at the A/C for 15 minutes the most, perhaps less. That can not be enough time to correctly address (even just identify) "strange" or intermittent problems. I think it was also reasonable for the Cap.n to accept the actions taken without questioning on the rationale (to each own his job) and just go for second T/O.