1999 Honda Accord Coupe, 2.3 ltr. engine. No air comes out (hot or cold) from my heating/air conditioning/defrost. Can you help troubleshoot this? I have checked the fuses, and tested the relay, all fine. Thank you

 

Apply power to the blower motor directly and see if it's faulty

 

If the blower is getting power and not moving then you need a new blower. You can get one at a junkyard pretty cheap (sometimes it even comes with a warranty) or buy a replacement at a place like AutoZone. If the blower is not getting power then you have a wiring problem or the HVAC controller is bad. I would be it is the HVAC controller. I have replaced mine several times with units from the junkyard, for a variety of failure modes. They're only about $15 at the junkyard and a new one is about 10 times that much. You also get to practice taking it out in the junkyard. There are YouTube videos on how to replace the AC controller as well as the blower.

 

could also be blower motor resistor in which case a/c will be shut down by ecu so a/c button light will be out.
reset ecu after replacing.

https://www.ebay.com/itm/Blower-Moto...BZNhBC&vxp=mtr

i like 4 seasons motors. lasts just as long as the factory units which is about 10 years:

https://www.ebay.com/itm/Four-Season...RXxvK4&vxp=mtr