Trying to use the heat, the auto-high or auto-low buttons do not work at any tempature. I think Tymbrymi has the answer. I realized there was a tempature sensor somewhere in the heating system, but I had no idea where.

One last question can this sensor be replaced or would I have to replace the servo?.....I think I know the answer to my question...replace the servo. If that is the answer I think I can live with the problem

I am going out and pull the two vacuum lines

All of you, thanks for your help

Augusta