The Nissan Path

My 99 has the digital climate control system. The a/c works fine and blows cold air that I can change from freezing to tepid but will not blow hot air even when temp is set to 85. Blower works fine and I can change the air flow up down defrost. Engine heats up ok and stays in middle range as usual. I am not leaking any coolant. I would appreciate any advice on what I can check before taking it to a shop. I understand there may be codes on the digital system to check but cannot find info on that. Thanks for your time in helping me with this problem.

There's a self-diagnostic procedure that can be performed if you want to get involved in fixing it yourself. You need to follow the procedure and steps in the factory service manual; you may be able to download one for free at Nico Club's web site.