this is just a post that will hopefully help a few people who might be in the same boat as i was. i purchased a '96 ek with an LS motor swap and found the heat was not functioning. the following is a troubleshooting path i did to find the heat problem. the blower fan motor worked (all speeds operational but only cold air blowing out). temperature gauge dropped to 0 when driving (changed thermostat to fix this but it didn't fix the heat problem). no blown fuses. the heater control valve was connnected properly to the cable and it opened and closed correctly. the two hoses that went into the firewall and connected to the heater core were not hot at all. there was no clog in the heater core as i ran water through it at varying speeds and it came out at the corresponding speeds. i called up a few honda technicians and told them my situation and the things i've already checked. they said that it sounded like there was a problem with the coolent flow so i checked all my coolent hoses and found that the outlet hose from the heater core and one of the hoses from the thermosat housing were switched around (after comparing it to a diagram of the B18B engine hose connection from an integra service manual) found them here http://www.homemadeturbo.com/f...912.0
i hope this helps because i wasn't able to find any posts or websites that contained the solution to my heat problem and i had to do a lot of troubleshooting myself to find the fix. my advice to others with heat problems are to check the easiest and least expensive parts first before deciding to replace something big like the heater core which i almost did and it would have sucked ***** to do that and find it didn't fix the problem.