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I'm chasing a problem with the automatic temperature control on a Lincoln mark VII. I found and replaced a bad wot relay. Now when AC is called for the compressor runs for a brief moment and then kicks back off. I bypassed the pressure switch even though it tested good and the problem persists. I have the FSM and the wiring supplement. In the wiring supplement there's a tsb listed for this circuit .. it's 91-25b-17.
Does anyone know how to find that tsb? I'm thinking this may correct my issue.

 

If you can find someone with an Alldata subscription they should be able to pull it. In the meantime, you can bypass that relay and see if it changes the behavior.

You could also try contacting this site and see if they can find it: https://www.tsbsearch.com/Ford?Page=318

Have you watched the pressure with a gauge to see what's going on when it kicks on? Could be the trinary switch isn't seeing the right pressures.

 

Ben thanks for the reply. I replaced the faulty relay with a NO one. It took me several hours to realize the mistake. Once I rewired to NC it works fine.

 

Lol.

Your always happy it's something simple, until you realize how dumb of a mistake it was and then you feel like a complete dumbass.

 

For sure I felt really stupid when I realized my mistake .. It's also stuck reading the temp in Celsius. I'm going to look into that next but it's looking like there is a problem with the controller. The electronics are 30+ years old and getting spotty. I may look into swapping a mustang heater box with manual controls.