'99 Newmar MA FW - only one furnace working

[1talltxn]

Howdy friends!

I've got a recently-purchased '99 Newmar Mountain Aire 39ft 5th Wheel. Dual A/Cs, and dual furnaces.

When I got it, the squirles had decided the front A/C unit was a fantastic place for a home. And of course they'd not liked the noise, so they'd chewed through all the wires on the roof.
With some careful staring at the wires and diagrams, we got the A/C working again.

All was well till this cool front blew through Texas and now I discover that the front furnace, I believe tied to the front A/C, doesn't function.

Got up there and looked at the wiring again, and all looks good. Granted, I don't know what wires actually go to the furnace as the owners manual for the A/Cs and the FW say "two wires going from A/C to furnace" but neglect to mention WHAT two wires.

The Dometic install manual does mention that with dual A/Cs and dual furnaces, the DIP switches on the zone 2 unit (front in this case) should NOT be flipped to indicate a furnace attached.

There's a single fuse for both furnaces and since one works, the fuse if obviously fine.

Anyone have any suggestions on where to start with this?
Thanks!

[1talltxn]

Update: Found a fuse directly on the furnace itself that was blown. Replaced that, and it started blowing. After about 5min, it started heating.
I presume because it'd been awhile since the gas was on to explain the delay.

However, when the t-stat cycled it back on later, it took another 5min to get to heat again.

Thoughts on what's going on here?