Honda accord climate control problem

Today my 99 Honda Accord V6 EX-L's climate control is all of a sudden
not working properly. I set it to 22 c degree, but it blows very hot
air. (Outside was 25 c degree.) I tried turning off the A/C and hoping
it can at least blow outdoor air in, but it keeps blowing hot air.
Then I tried completely turning it off. Still no luck. The opposite
thing happen once last winter, when it supposed to heat but instead it
blew code air. Most of the time, the climate control has been working
great. Wondering if anyone has any insights, before I bringing it to
the dealer for check up.

 

wrote in @h2g2000hsg.googlegroups.com:

The heater control cable has probably slipped off the heater control valve.
Check under the hood, near the firewall on the passenger side.