My A/C works great but from time to time the heat will suddenly come on. I get hot air out of the defroster vents and warm (74 degree F.) out of the dash vents. I checked to see if the monovalve was receiving full voltage when this was happening and it is. I replaced the insert last fall because of no heat.
If I turn the car off for awhile it will usually correct itself, though sometimes it doesn't, and wheather the heat is flowing or not makes no difference in the voltage to the monovalve. It seems to never happen when the car is started from cold, and when it does after awhile it seems the longer it sits the more likely it is to be OK when I start it again.
I followed the great DIY instructions I found here last fall when I changed the monvalve insert but one thing I couldn't determine was which way the notches in the metal sleeve the coil slides into should face. Is it up or down? I've had it both ways without there seeming to be a difference.
Here's one more hint. If the A/C is working great and you move the dial off its coldest setting the slightest amount, the heat will come on and won't go off when I turn it back. There will be full voltage at the monovalve either way.
06-01-2008, 08:12 PM
Linear Mode
