Aqua Hot Heat Exchanger Access

The 20 amp fuse that controls my Aqua Hot heat exchanger fans pops every time I try to use the AH for heat. I suspect I have a bad/shorted fan motor in one of the exchangers. I can get to the exchanger under the bed and it works fine as does the exchanger under the galley/stove. However, I am curious how to get to the one under the dash (all it has is a small grill on front and no access from behind) or the one in the water bay.

Anyone with a CC or similar set up have any suggestions?