Thanks all. I swapped the fans, and the problem follows the fans, not the connector position on the PCB.
New fans ordered.
Thats pretty common with s4's at this point. The fans are starting to die on all the ones I had.
S4's are kinda dated at this point and most likely a lot have had multiple owners. I know I sold mine long ago and upgraded to S5's at the time. With them getting older having a extra fan on hand is a good idea. If multiple S4's maybe even a few, and make sure to clean them they can get very dirty over time. I like using compressed air personally, and if any dust on fan's wipe them off.
I owned a few a while back and only had to replace 1 fan. I used on of the sanyo's from the article they recommend, think I got it from Amazon at the time. But having extra parts is really part of mining to a certain point specifically if older gear.