EATC replacement

Greetings...

I have a '98 Crown Victoria. It has had a problem with the EATC. I read the posts here and in the Mercury Grand Marquis forum. I did the self test and got codes 024 and 025. My symptom was that it suddenly started blowing hot air when the AC was on. The AC was charged and hoses were getting cold. Now that it is cold, it blows hot air like a blast furnace no matter what the temp settings. It is easier to live with in the winter. I can turn it on and off to get a reasonable temp for the commute.

Deciding I was out of my depth on this fix, I took it to a shop which did some diagnostics. They say it is the EATC module. They got a rebuilt one and installed it. It worked 20 minutes, and I took it back to the shop. They put in another rebuilt one and this time it lasted 40 minutes before I had the same symptoms. I took it back again. They replaced it with another rebuilt module from the same place. This time it worked about a day and a half.

I don't hear clicking from the blend door, but when the thing is working, the heat modulates between pretty warm to pretty chilly. You can feel it with your hand in front of the vent. Once it is stuck on full heat, you can run the self test and reset it to get it working again for a while.

I am trying to decide what to do at this point. Do I take it back for a 4th rebuilt module? They are doing them under warranty. Do I offer to pay the parts price difference for a new part? Do I give up and take it to the dealer?

Thanks... Tom