Had to do the same thing. Bought my 98 Allure just before Thanksgiving, it had spent it's entire life in the desert and evidently the previous owner(s) didn't need OTR heat. When I investigated, I found the hoses tied together up front with a pipe nipple to prevent the compromised core from leaking. The core was toast and needed replacement, it didn't warrant repair. It was an all day (9 hour) job from start to finish for two of us with average DIY maintenance skills. The core was $250 from CC, local mechanics in my area are $100/hr (+-) and had quoted me $13-1500 plus parts. I learned a whole lot about what's under the dash and satisfied myself that nothing else was leaking or needed attention plus saved a bunch of cash. It's not difficult, just time consuming. Sorry, I didn't take any pictures. Good luck!!
Chief G CMSGT Retired
1998 Allure 36' Rogue #30197 325CTA w/Banks. Arlington,WA