Bubbamax

I have a dimensions one Aurora 2 mine started with a flow error I pulled the flow sensor out cleaned it off and reinstalled. Changed fillers removed air out Flow error went away The next morning went out and had high limit error turned gfic off to reset error and noticed a flash in the disconnect box. So I turned main power off to inspect disconnect box gfic breaker. I found the lug on the gfic must have been lose in the disconnect box. So I removed the gfic and wired it Direct to trouble shoot if I had bigger problems. I turned the main breaker back on had a flow errors unplugged flow switch and plugged back The error went away and the next day I had a high limit error. I’m wounding if I have a bad flow switch it will cause a high limit or do I have bigger problem? I know it a 2004 and don’t want to put a lot of money into its seen it better days. But have been a great spa. Any help will be appreciated