A/C not cycling - no heat either

[ducboy]

I have a 2000 Mazda B2500 with a 2.5 liter four cylinder. 2 wheel drive, manual trans with A/C. My A/C compressor will not cycle regardless of the setting and there is no heat when I attempt to use it. Checked all fuses and relays. Swapped known good relay to the A/C circuit. Still no-go. Consulted my Haynes manual and found little help. Cant determin which is the WOT relay. Manual says to check this. Read another thread that one user said he replaced the "low pressure switch"

Anyone have some help here??

Thanks in advance.

P.S. I'm in Wisconsin and I'm freezin' my #*&! off.

[Ultramagdan]

Have you checked to see if the compressor is cycling and if the hoses to the heater core are hot? I would suspect a blend door problem if the rest of the system is ok.