replace the heater temperature switch
check the fuse or the ground on the heater
have you checked the engine thermostat. I have a similar problem..no heat or air. according to a service manual there is a door at the heater core that is supposed to open when the heater switch is turned on. this could be the cause for both of our problems. any ideas for getting to the heater core?
fuse or relay most likely
Check your heater core also.
it is either a bad switch on your controls, or your blower motor is going out
Check your fuses for these devices. Or while under the dash you have accidentally unplugged them.
Sounds like some one hooked it up wrong.
Sounds like heater core is leaking
Your heater core is leaking.
fit a new indicator column switch
A heater bypass is not an original equipment item. you would install it to keep coolant from circulating through the heater core, mostly when it is leaking.
The heater core is plugged. Blow it out with a compressor. If that does not work replace the heater core.