Originally Posted by fgmartyr
I have a 2004 grand cherokee 4.0 that i am fixing to install a pcm into. My question is does the pcm have to be bolted directly to the firewall for grounding purposes?,or can i install rubber groments behind it to cut down on the vibration which could cause one to fault.
If you isolate it, the only difference would be that you might want to run a small, short, ground strap from the case to the mount.
Since I dunno if mounting it to the body is done as an RFI protection, make it a short, wide, ground strap.
You might actually create more vibration if those rubber grommets allow it to slop around, unless you have something like silicone or similar. Not saying its a bad idea, but it could make things worse.