Service Engine Light

Hi all
I just wanted to update you on my electrical problem with my 1989 GMC Truck 305 , 700 r( electronic control) non modified. (Service Engine Light fading out when I try to read the codes). I changed out the Oxygen Sensor but that didnt work. Also changed out the Throttle Position Sensor because I was getting a code 22 ( or thats what It looked like, the light faded and couldnt read it that good), but that didnt work either. I then changed out the Torque Convertor Solenoid and so far so good. My light has not faded since I replaced it, but I havent gotten enough mileage on it to tell if I'm going to get a code. Hopefully I wont get one, but if I do, at least now I'll be able to read it.
The easiest way to check the TCC Solenoid if you are having this problem (fading light) is to mash your brake while you have the code reader in and key on, (but engine off). If it doesnt fade out then the TCC is probably your problem. You can also unplug the sensor from the transmission, but mashing the brake is much easier for a quick check. There is a switch on the brake that breaks the circuit.
I'm keeping my fingers crossed, hopefully this has solved my problem.
Thanks again for all the help, I'll keep in touch