I have a 1990 Riviera and I have a very frustrating problem. Similar to another qustion here car won't start. Everything turns on, lights, radio, etc., I can hear the fuel pump going even, but when I turn the key, the click from the relay is all that happens. The frustrating part is this only happens when it's gets wet, after snow melts or after driving in the rain. Gotta new starter, new fuel pump, still when whatever it is that gets wet does so... NOTHING. I can't find a relay for the starter and I'm kinda at my wit's end. Any and all guidance is greatly appreciated. Thanks.

hmmm
neutral safety switch?

I'm guessing here. We used to have an '86 and we had that happen a couple of times, but holding the key in the start position or turning it in and out a bunch would eventually start it.

Sorry that's not very helpful I know... Check the NSS, try wiggling the shifter while you are trying to start.