so i was driving my 2001 blazer 4x4 and it wouldnt shift. well i was driving slow and felt like a little loss of power. but when i steped on it to get onto the hwy it wouldnt upshift but it more felt that it started to slow down and loss power but the petal was to the floor. now i cant even slowly accelerate qnd get it to shift. i am lost i have replaced the engine and diff already . well also had to replace the headers before and when i went under the car noticed that on the drivers side of the vehicle along where it looks like the shift linkage is. there is some melted wires one being the o2 sensor but where the wires go there is another set of wires that look melted to but not sure. tried to fine what the wires were for . just need this suv running due to its my wife's only way to work since she cant drive manual. will try to take pics of the wires tomorrow. also there is a check engine light on, but since this vehicle wont go past 30 mph havent a hard time taken it to autozone.

 

CEL is probably on due to the melted O2 sensor wires. The other wires probably do run to the transmision. It is a 4L60E right? Check this thread out. It gives some pretty good wiring diagrams as well. LINK CLICK HERE.

 

If you have melted wires, you need to repair them.

BTW, great link Oisinirish!

 

thanks i will definitely fix the wires.

 

wires are fixed. but still have the problem. i got codes for the check engine light. P0101, P0404, and P0756

 

All of those codes are listed in the OBDII Code Index (link in my signature).

 

Any luck? Fightign an electrical issue on a 94,000 lb excavator right now...now how it goes. Zener diode?!...how do you test one of those without a load tester?

 

I would start by cleaning the MAF and pulling the EGR off and cleaning that, making sure that it is not stuck open or closed.. then clear the codes and drive it for a while and see if there is any codes that pop back up, if the P0756 comes back it means Shift Solenoid B, aka 2-3 shift solenoid valve performance is not operating as it should, and you should have it looked at