1996 Sable - Heater is wacko! Confused.

[qsecofr]

Let me tell the entire story so you have all of the facts.

a) Everything was working just fine when my AC clutch had a bearing break and the clutch entirely broke off of the AC compressor.

b) Bypassed the AC compressor with a shorter belt. I thought I was so smart.

c) Driving a couple of weeks later and noticed the temp gauge was about to break off because the engine was HOT. I slowed down (it was while driving on the hwy at about 70mph) to about 25mph and the temp gauge dropped back down to normal. I decided the temp problem was most likely due to the shorter belt not turning the water pump properly. I pulled off the hwy and checked the coolant level to find it all boiling out of the overflow. I added coolant to get it back to normal levels. I tried to turn the water pump with my hand and it turned easily so I know the belt was not resting against the water pump properly.

d) Noticed my heater does not work any longer. Something about the high temperature problem at step 'c' above caused me to no longer get heat.

e) Replaced the AC compressor. I could not do this myself it was just to difficult with the S engine. I purchased the AC compressor and dryer and paid a local garage to do the install. They were able to recycle my refrigerant so it saved me in the long run.

f) I had the garage replace the thermostat (due to the no heat situation) while they were under there replacing the AC. I figured better do it now rather than come back and try later.

g) AC appears to be working great but still no heat. Now I began to believe maybe the heater core is plugged. Maybe it got plugged up when the high temp situation occurred in step 'c.'

h) Driving around three days after my new AC was installed and WHAM ---- Now my heater is on constantly. I cannot turn off the heat. It is roasting me out of the car.

Does anybody have any ideas as to what is broken? I can turn on the AC, vent, defrost, anything and it is blazing hot air. The temp control gauge doesn't seem to make any difference.

My Sable repair manuals do not say anything about replacing the temp controls. I have no idea what I am looking for. I looked around behind the glove box and under the hood for a in-line switch for the coolant into the heater core but could not find anything. Then I noticed in another thread the maybe this is vaccum controlled. I am lost.

Scott

[qsecofr]

Update.

Now the heater is working perfectly. No idea what is going on but now the cool blows cool and as I gradually move the temp gage to hot it gets warmer and warmer.

Am I dealing with a vaccum system here? Do I need to check for vaccum lines or something?

[qsecofr]

Now it works some of the time. It can only blow either cool or hot air. This is random. I guess the mechanism that controls the temp is malfunctioning. I double checked the coolant level and it is totally full. Nobody has responded so I guess this has a bunch of people scratching their heads.

[DistanceGuy1]

This may sound odd, but a while back I too had an odd ball problem that I am sure had people "scratching their heads", can't blame them either.

At any rate, as most of the Sable's part are shared with the cousin "Taurus" I took a chance and posted it issue on that forum. Lo and behold 2 folks responded and one had it right. Can't hurt...