I appreciate your follow up on this Swartlkk! I discovered your earlier post with the pictures after following your initial advice to google the deep/shallow pan question. I edited my previous post after seeing the pictures and having another look at my pan.

Thanks for your help! BT

 

After a long wait for new parts, I finally got back on the Blazer over the weekend and pulled the pan on the transmission. I replaced both Shift Solenoids A & B even though the old solenoids both tested good at 22.4 ohms. A close visual inspection of the transmission's internal harness revealed no obvious problems. I then installed a new filter, buttoned it all up and added 4 qts of new ATF. A test drive was delayed by a rusty, leaking front to rear steel brake line on the driver's side frame rail. After fabricating a new brake line and bleeding the rear brakes (more on that to come eventually in another thread), I cleared the five codes and then took it for a ride. The initial signs were good with no SES light and the transmission shifting up and down normally at various speeds, with a number of starts, stops, backing up, etc for about 15-20 miles around the neighborhood. Unfortunately, just as I was pulling back into my own driveway, the SES lit up and the scan tool showed a hard DTC P0758 (Shift Solenoid B) and in addition, all five of the problem codes showing as pending. Looking at the bright side, I was pleased at least, that my first venture into the innards of the transmission resulted in no additional harm but I was once again right back where I started. That is, an intermittent case of the five code tranny blues!

So I am still searching for an intermittent open somewhere in my transmission control circuit (1020) and I got started again today with a test light and multi-meter. Once again I am fairly certain I've confirmed the integrity of the circuit from the ignition switch through the cluster fuse 11, C203, P100 and the body (power) side of C101 as with the key ON engine OFF, my 12v incandescent test lamp attached to terminal G on the Body side of C101 stays lit despite any pulling, tugging or massaging any of the body side wiring I can get my hands on.

My plan for tomorrow is to get the Blazer up on the lift again, disconnect C175 at the transmission and test for continuity in the chassis harness between terminal G on C101 and terminal E on the transmission connector hoping to find something awry in that portion of the circuit. Any other suggestions are welcome!

One additional note and request! I've been using an OEM GM Service Manual from my previously owned 1998 Blazer though my current problem is on a 2002 Blazer. I just noticed today that Connector C101 in the 1998 Manual shows a 10 cavity male/female connector, while C101 on my 2002 Blazer has 16 cavities. While it probably doesn't make any difference in the circuitry, if anyone has access to a Connector view of C101 from a 2002 Blazer SM, I'd appreciate it if you could post a copy of the 16 cavity diagram.



It also appears that someone has been into this connector at least once before as the closed loop end of the little pink strain relief "toggle strap" between the two halves of the connector is looped around only one wire (the wire just adjacent to the pink circuit 1020 wire) instead of going around the entire bundle of wires going into the chassis side of the connector. Once it's all connected, the little nub on toggle strap loop just happens to press into the pink wire of circuit 1020 which may very well have caused a break in the wire inside the insulation. In fact I'd be pleased at this point to find this is the case and will be looking closely at this spot when testing for intermittent continuity between here and the transmission. If so, I'd appreciate any help on how to remove, re-splice? or re-crimp this individual spade terminal in this type of connector. There is a little pink clip snapped on the back of the connector that separates the individual wires where they go into the connector. If this pink clip is removed can the individual spade terminals then just slide out? I'd like to reinstall the strain relief strap with the fixed loop around the entire bundle rather than just around one wire. And if I do find a broken pink wire inside there, are these spade terminals available anywhere so I could cut off a bit of the wire and re-crimp onto a new terminal?

Thanks in advance for any replies!!! BT

 

Reconnected C101... Pulled transmission connector C175 and attached 12v test lamp to terminal G. Key On engine off and test lamp lit up and stayed lit no matter what I wiggled, pulled, or shook. I am unable to replicate a loss of voltage in circuit 1020 from the cluster fuse 11 to C175 at the transmission!

That seems to leave only 2 possibilities... An intermittent fault in the transmission's internal harness??? Or, an intermittent fault in the ignition switch??? SO...

I had previously ruled out a bad ignition switch because my instrument panel continues to function normally when the fault condition occurs. Is this not always true? Has anyone ever seen a bad ignition switch causing the five code limp mode problem without losing the instrument panel too???

Or, should I be pulling the pan again and checking for voltage at the individual solenoids while wiggling the internal harness with the key on engine off???

I still have a little hair on my head but can't afford to lose much more of it!!! BT

 

Had a good day today! I won't bore anyone with the details but I finally found the problem! Still not sure about how best to rectify it but eventually, I'll figure that out too.

My thanks to everyone who helped! BT

 

Don't leave us hanging......What was the problem?? Nice work sticking with it!!