4wd problems. My 4wd would not engage, the buttons would only blink

No I have not. My local mechanic said scans don't tell the story, and suggested replacing parts.

You need another mechanic, how do you consider we fix problems not throw parts at them. If you would find someone with a Tech2 scan tool you would be able to read the transfer case control module and find the reason for your problem. I guess your mechanic is not familiar with a good scan tool our doesn't know how to read one. I scanned one the other day with an A-B circuit malfunction and cleaned all the grounds, and it left with a happy customer. He even gave me a good tip $100.00 for fixing it. He was told to replace the encoder motor, that's over $300.00 new at the dealer. Don't know how much you have spent, but it could have been a lot less.

I had the tccm scanned. the codes were co379,co327,co550,co300,co305,co306,co321,co327,u1301,u1155.Now what does that tell me? Switch,axle motor and transfer case shift motor/encoder have been replaced. What next? I still can't find a schematic or flow chart to give me a way to check power in any kind of order.

It doesn't tell you anything, but tells me everything you did on the truck. It starts with the front axle malfunction, control module malfunction w/ loss of communication twice, rear diff sensor, front sensor performance, transfer case lock circuit, encoder circuit, & motor A-B circuit. That's a lot of information, but now that some of these could have been caused by you working on it and changing parts, and cycling the key in the process. Now didn't I see that you changed the TCCM or had it fixed? not sure it was you or someone else, anyway the first thing I want you to do is clean the grounds on the frame at the front left cab bushing. There are 2 or 3 grounds on the outside of the frame. The go to the battery and there will be a small ground on the ground cable going down to the frame. Clean that one at the frame very good. Next you need to have the codes cleared, and try the 4wd to see which codes go away and which ones come back, if any clear or return, and let me know which ones came back.

I didn't do anything(to the TCCM) except disconnect the battery and remove the TCCM to see if any of the pins were corroded. I then re-installed it. But I did disconnect the grounds under the driverside frame and cleaned them with a stainless steel brush,sprayed w/wd40 and re connected. I will clean the battery cable ground and clear the codes and try again. PS. one time during the process I had the car washed w/under carrige wash and the 4wd worked. An hour later it was not working..............

Sounds like a bad connection.

Ok. I cleared the codes and cleaned the grounds. I tried the 4wd again and the only code that comes up isCO379. I think that is front axle code. It has a new motor. Is trere something that can stick and cause the mkotor not to work? I think we're getting close!

Check the grounds up by the left engine mount. Follow the wires

OK, Cleaned battery cable ground and small gnd. Tried it again, samething. I did ck. the front drive shaft an the transfer case IS shifting. I pulled the front axle motor and I can move the sleeve and engage the axle by hand but I get no movement on the axle motor with the switches. Checked the front axle motor plug to see if I had a broken ground wire. one pin read to ground and another wire read with resistance. Which pins should get power and what voltage. I don't think the axle plug is getting power. I finally found a friend that had all data and he printed a schematic.With that info I was able to find a wire with high resistance and replace it. Problem solved.