550 click after draining battery

I unwittingly (stupid, I know) left the key on my 13 550 eps 4×4. Drained the battery…really dead. I put a charge on it for a few hours and it didn’t improve.

I figured I toasted the battery so I unhooked everything and pulled it out. Decided to charge it on the bench for 24 hours. Low and behold, it charged. I hooked everything back up (winch, handwarmers) and all I got was one click. Just hooked up the positive and negative from the wiring harnesses. (2 positive and 2 negative). all I got was one click. everything powers up fine…. fuel pump, headlights, winch works…hit the key…one click.

I turned on the lights and tried to start it to check for a drain but the lights didn’t dim and one click. tried neutral….one click.

Finally, I found the starter relay (right wheel well) and turned the key while touching the relay. I can feel it click one time…each time I try. I tried to jump the relay but it didn’t do anything..no click…

LONG story short (sorry)…Could that relay be bad or one of the relays under the front cab? I don’t want to just start throwing parts at it….

thanks for any help…