See if the PCM isn’t actually sending a ground signal instead of a positive to trigger the relay.
Never heard of a 3 legged relay? Like stated a four or five.
Only three things I can think of assuming the relay is in fact good. (I’m trusting you swapped with another)
1) a 100% bad range selector switch or wiring from it to PCM. However I’ve never seen one fail in both neutral and park positions.
2) a bad PCM but doubtful
3) a broken ground in the starting circuitry.
How many tabs are on the actual relay? It wouldn’t be the first I’ve seen where the wiring came loose and dropped inside the fuse box. I’ve seen it at least twice on cooling fan relays that got a tad too warm.
You could really use the help of alldatadyi.com and it’s easy to navigate diagrams and definitely a powerprobe.
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