It's to my understanding that all 89 Camry automatics are electronic shift. My 88 I4 has no specific trimline, but it still shifts electronically. I have a ECT in my car.
I never recall a Gen2 automatic without the ECT.
Anyone?
My first recommendation is to get yourself a Toyota 88 shop manual. You can probably get one used in good condition on Ebay. You will find the wiring diagram in there. Haynes also has a wiring diagram.
Good luck in resolving this issue.
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88 I4 Slushie, 89 I4 5Sp, 89 V6 5Sp, 82 Corolla, 72 510, 88 Minitruck.