I was checking the pressures on my AC and I think I screwed up and broke my gauges. For some reason I opened BOTH the high and low side valves at the same time while the truck was running. Now my low side gauges is stuck wide open. Is this because my high side was around 250? I looked everywhere online and it never says NOT to do it but common sense (in hindsight) would say not to correct? By doing this do I not bypass the condenser altogether? (As in high pressure would flow through the open high pressure valve in manifold set, through the "utility" chamber, then through the open low pressure valve)? Did I permanently damage my gauges?

Is it EVER ok to open both side of manifold except during the vacuum stage?

 

No.

Yes. You sprung the spring, most likely.

If you're lucky, you may be able to remove the lens and free the needle with probably overran its stop.

Otherwise, you can buy replacement individual gauges on Amazon or eBay. Neither of the gauges on my manifold are original, I've replaced each of them at various times. They're not very expensive.