Since you've got it in three places, you could use a combination of these phrases, to avoid redunancy. Examples of the usage (not necessarily how you would translate these entire phrases, just examples of the term I'm proposing):

If the CGT card fails (or gives out), it takes out the CGT relay...
If the UC makes the firewall crash, then it no longer sends...

JG

Jennifer is right, it is hard to find one phrase for each occurence, maybe this one works!

Despite Alex's compliment, I have to say that I don't know much about what's going on here; however, I'd just like to chip in to at least sound a note of caution.

Alex and I are both assuming that these 'relais' are actual physical 'relays' --- it's kind of reassuring to note that when all the clever electronic gubbins packs up, there is a nice, solid, nuts-and-bolts sort of relay standing by in the background as a safeguard!

However, I am at a loss to know just what this 'watchdog' would be, and hence, whether it's a physical entity or just some kind of software.

Alex's suggestion of 'trips' WOULD be OK, except that in the case of this sort of 'fail-safe' mechanism, it is usually a case of a relay becoming DE-energized; this could be regarded as being the opposite of tripping, as 'tripping' can imply 'on' as well as 'off'. It might be safest to say: 'trips out', or as I suggest, 'drops out' --- a very common term used in relation to relays.

As for this 'watchdog', clearly if it isn't a physical entity these sort of terms will sit uneasily with it, and I think in that case, Jennifer's 'takes out' would probably work best.

As Jennifer says, it may be hard to find one word to fit in all these places; certainly, it sounds very odd to my ears to say "crashes OR takes down a relay" (unless, of course, that's 'relay' not in the physical, but in the software sense)

brings down xxxx/makes (xxxx) shut down