IT IS a lot easier if you can discharge the a.c and then recharge but if you remove the blower motor housing and then take the nuts off of the mtng studs that hold the ac evap, to the firewall and then pull the evap back ward toward the seats and then gently move it to the right it will move about an inch and then you should be able to snake the heater core housing out ,, after the dash board and the surrounding plastic trim is remove , also remove all the controls for the a.c. and heater it will give you a bit more room and you willneed all you can get , they have to be disconnected from the htr box anyway , Jerry