Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Hi there, I am Cam.What exactly is your transmission doing?
Hi Jim, so what is going on with your truck/transmission?
Does your speedo work properly?Do the brake lights work?
Is there any aftermarket devices installed like a remote starter or such?
My first thought is a bad ground wire. I would check the grounds down on the frame, check the wiring for grounds on the intake manifold and around the engine bay. Then I would look at the ignition switch. One feed is for the transmission and such and if that is limiting power, it would cause this.
Test by accessing the thick wires at the ignition switch. With your multimeter set to DC volts, place the red lead on the red wire. With the switch turned on, test the other leads with the black wire. Record the reading and let me know what those are. Repeat the test on the red/white wire. Let me know the results.
OK so lets look at the power.
No, the test measure voltage drop over the switch, red probe to red, black to each other power wire.
Those sound right, so I am thinking wiring at the transmission, wiring at the ECM or the ECM itself.
Then wiring or connections will be your issue. Finding it could be difficult.
The ECM is the transmission shift module.
OK, did you look at the wiring inside the transmission then?
Hard to say. IT very well may be related, but with some of these oddball cases, diagnosing over the internet has its limitations.
Does Tapping sharply on the housing of the ECM change how it runs?
Or makes it act up or sop acting up?
Try tapping and see if it changes anything. IF so, replace the ECM.