From the top...
Early last year my speedometer, odometer, and fuel gauge quit working at the same time, and the check engine light came on. Since I don't drive fast and work at a gas station I thought I would just deal with it till I needed an inspection, thinking this was probably an easy fix
Had a guy run a diagnostics test on it, and got a few different codes the main ones were speed sensor, idle control, MAP sensor. He told me that if the ECU does not know the speed it will cause other sensors to be faulty, but he had a throttle body with all the sensors off a working vehicle laying around so I went ahead and switched them out. Well my inspection has run out, and here are some of the things I replaced/tried:
1) I replaced speed sensor.
2) Replaced throttle body and sensors.
3) Read a few different threads that said it could be a bad ground connection, so cleaned the ground connections.
4) Checked all the fuses under hood and behind kick panel.
5) With a test light I checked to see if I had power going to the sensor while Jeep was running and no power.
6) Checked wires from speed sensor to the main wiring harness.
After all that I tried to find out which wire was the one supplying power to sensor, and chose the purple/orange wire because I found one of those going to the PCM. Also I want to point out that this wire had power directly after PCM, but the purple/orange wire at the speed sensor had no power. I heard or read somewhere that the white/orange wire works the speedometer, so by process of elimination I went with the purple/orange wire, thinking the other would have to be the ground. I may have been wrong, so can anyone help me with this. I then stripped away a little of the purple/orange wires insulator directly after the PCM and right before the speed sensor. Then tied a wire in, making sure it was receiving power, but when I went to start the Jeep it would turn over but not start. I then took wire back off and still no start. I can't hear the fuel pump prime, but checked all the fuses and relays and they are fine. I think I may have made a mistake can anyone help me???