98 B4000 Heater Control Blows HOT on COLD position

Does not always happen..sometimes I can get COOL air on the COLD
position other times it's HOT air all the time. Is the valve inside the
engine bay on the passenger side ? Looks like a vacuum valve on the
heater hoses.

I am not sure, but suspect the Mazda used the same heater/AC system as
Explorers of that time? If so, you are describing classic heater blend door
problems. The shaft to the blend door was fragile in the original versions
(replacements use a different plastic) and would leave you with hot air all
the time except when selecting MAX AC as that position also operated a hot
water valve to shut off flow. Lots of official and less-expensive
alternative fixes posted, do an archive or google search.

=Vic=
Bear Gap, PA

> wrote in message
ups.com...
> Does not always happen..sometimes I can get COOL air on the COLD
> position other times it's HOT air all the time. Is the valve inside the
> engine bay on the passenger side ? Looks like a vacuum valve on the
> heater hoses.
>