Lowe's goal moved Guiseley back above their Yorkshire rivals before the squad had a nervous wait for the Minstermen to finish their match against Forest Green Rovers.
The Lions started the final day outside of the relegation zone but were on the cusp of a drop back into the National League North after falling behind in the first half.
Solihull saw a penalty kick saved by Dan Atkinson early before Omari Sterling-Jones put them ahead on 26 minutes.
John Parkin's brace for York City twice pulled them level against Forest Green, which left the two Yorkshire sides equal on points with the Minstermen enjoying a greater goal difference.
However, the relegation battle had a dramatic climax as Lowe got on the end of Danny East's long ball to send Nethermoor Park into pandemonium.
The Guiseley squad waited on the pitch until news arrived of York's failure to score an injury-time winner sparked more celebrations.
It is the second year in succession that Guiseley have pulled off a great escape in the National League.