I'm trying to verify the transmission is defective.

My 1991 mercury tracer will not shift into torque converter lockup. This may be defined by saying the trans will not shift up the last time. I am going at 4000 rpm when at 70 mph. Usually I am going at
3000 rpm at 70 mph. The ecm sends a message to lockup. I would like to manually jam the signal ON to verify the trans can or cannot be locked up. Does anyone know which connectors and which electrical lines cause lockup?
Thank You, Dan
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Your kind of missing the boat. Torque converter lockup can happen in 3rd gear. So it's possible it's not shifting into 4th, and you interpret that as no converter lock up. A good scan tool with proper display will tell you what the gear range you are in and if the converter has been commanded to lock all while you are driving.

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I have decided to take your advice. The car is now at a local transmission place for diagnosis. Should know by this evening.
My cause for concern is because of my old 87 dodge caravan. The transmission was "rebuilt" at a cost of $1200 only to find out that the repair place did NOT reconnect the lock up connector. Once i found that, a number of months later, I had the same chatter as I did before the repairs. I was suckered into a $1200 loss there. Only to have the trans begin to leak, the dealer replaced it with a new one for $1400. Couple thousand miles later the engine went so I junked the van. The van had about 109k miles on it.
The tracer has about 60k miles on it. Have replaced the heater core. That was a time sink ( about 3 months) at an hour or so a week. The rear springs have broken, both sides. Strange things have gone bad. Don't believe I like Ford stuff. Oh, the timing belt broke when my daughter was on her way back to college. She was stuck on an interstate for a number of hours.
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