Maybe both!!!! LOL
phillip_g questioned this in another thread, what I had yet to learn is that the auto and manual work opposite of each other, and set up opposite of each other. With the RENIX:
Auto tranny output voltage starts high at closed throttle, and drops as throttle is opened.
Manual tranny output voltage starts low, and increases as throttle is opened.
Past that I defer. Before I discovered this valuable resource, I went to my local library and used their subscription to ALLDATA. In that system I used vehicle specific filters. So if you have a '90 Limited, ALLDATA will have me repeating the correct info. LOL
hockey, langer1 mentioned the ground connection. Just for grins measure between pin D (the ground wire) and the intake manifold. ALLDATA says that if there is more than 0.1 volts, you have an inadequate ground connection. ALLDATA recommended tapping the ground wire and adding another ground point. When I measured from pin D to chassis ground I had 1.0 Volts. Where-ever that wire grounds, it had too much resistance! A second ground point under the hood fixed that problem.
Past that I had an extra set of hands to help me. I struggled by droplight 'till frustration got the better of me. The next afternoon, my wife came out and held the meter while I used the probes. I sorta wish I had got that frustrated much sooner. LOL
Hang in there, Mike