tcc not locking up?? any way to manually lock up?

[ff43sc]

I have a 95 k2500 6.5l, has 4l80e, the past 6 monthes or so, truck seemed to be running higher rpm's at highway speed, had timing/tdc offset checked and it's correct, Used actron scanner which shows TCC applied, YES, TCC Lockup NO, Slim rpm's constantly change, lowest is 10-20's, and tcc solenoid always says off. Tranny shops so far haven't been able to tell me what problem is, One earlier post suggested maybe faulty TCC solenoid, I replaced that with no change. is there a way to manually switch the TCC solenoid on, and does this sound like a PCM problem, or tranny/wiring harness problem. I feel difference when TCC Applied happens, and rpms drop. but still not the rpm's and quiet ride I had experience past few years with this truck, Thanks for any help.

95 GMC k2500, 6.5l F, 194,000 miles...

[rjwest]

May want to check wiring from PCM to Connector...
With OHM Meter

Also attach a Voltmeter to Lock Up feed circuit to
see if PCM is Changing Voltage....
I think you can ground input to TCC solniod,
to test , but not sure,
Some one will probably give you more info shortly..

I had this problem on a 60le Transmission (93)
( I know its not quite the same.) Disconnected all
input plugs to trouble shoot, when I reinstalled
connectors, problem went away. ?????

[rjwest]

Sorry, Should read: Removed all connectors from PCM box...