heater no longer functions

[Warm Pudgy]

Winter is here and the heater only works when on the highway or when the engine is at high RPMs (>3k).

Any other time it just blow air.

If I push the temp knob and turn the system to auto, the lcd turns on but the fan stays off.

Then if by chance I take the highway instead of going thru the city, the heat will eventually turn on. If not, then it never will.

The engine is cleary warming up. The temp guage sits right in the middle. Sometimes right above it.

When the heat does actually turn on, it blows nice and hot.

I have no idea where to even begin with this

 

[Bushwhacker]

Thermostat stuck in the closed position?

 

[Warm Pudgy]

Oh I forgot to mention that I've changed the thermostat 3 times since this problem started

 

[samsdad]

My Surf did this recently but was the other extreme.. No A/C till higher revs. While it doesn't have the digital display rather the old slide type and fan switch it still has an ecu to control the whole lot (AKA A/C amplifier). In this instance the regulator in the alternator had shat itself so the whole lot had a bit of a fit and shut down. One new alternator later and end of problem