a/c leak

You stated you 'resealed a/c last year'

What/how did you reseal???

We in fact have never used the a/c as we are never anywhere that has mains power. Have used it at home a couple of times while we were using the rv as a bedroom. May just remove it permanently.

Good Morning J.D. yes ,we still have it .I am going to take the a/c off completely for the winter ( trust me we don,t need it in Colorado during that time ). Then seal the top with a square of ply . I have read a post where the person used some wood between the inside framing and the roof to get rid of the depression and thus stop water pooling. Hemi RT the sag is not that bad and there is no rot.

Rod, If you still have that Holiday Rambler (and I wish we still had ours!) that roof should have metal trusses and hopefully metal framing around the A/C "hole." Think I'd consider using synthetic material, though. StarBoard is a brand that comes to mind. It's gotta be done well, though. You don't want to trap water between the roof and your new patch.

How big were you planning to make this? It'll take a fair bit of margin to keep the patch from distorting.

If the roof is sagging, you have a bigger issue with the roof rotting.

check the bottom pan for the a/c, it maybe cracked which is very common