Pontiac Problems? Ask a Mechanic for Answers ASAP
Does the pushing on the relay/fuse box work every time?
I would suspect to see a ton of corrosion or rust inside that relay box if that's the case. You might start by removing the fuse box and looking for signs of corrosion, or burn marks in the circuit board.
There are a couple of voltage feed wires leading from the fuse box to the interior wiring harness, and one large red wire feeding voltage to the fuse box. I would check that to make sure it's tight, and any ground wires on the frame nearby need to be clean and tight also.
There's a good chance the relay sockets might just have some corrosion in them. You might get some dielectric grease and fill the relay sockets with it and then plug the relays in and see if the problem stop happening.