2009 Chevy Tahoe LT 5.3 No Crank!
Read all kinds of threads on grounding and power connections. Jumped starter at relay, ok. Changed both power cables, cleaned all ground connections and tightened. Changed Ignition switch. No crank. Found a high tech small shop. They spent a couple hours. They had a GM Instructor buddy who brought some cool (high tech gm troubleshooting tools). They found Ohm issues on the common computer BUSS. (Grounding out or shorting out). Then ended up Tracing it to a harness going to the trans (in the bundle it self). The trans connector was good. They re insulated / replaced the common computer buss (high side) wire in the bundle from the transmission to the ECU or TCU.
Problem solved.
They only way to see it was to have a breakout box, watch the ohms and see them go crazy when they shook the harness.
Read all kinds of threads on grounding and power connections. Jumped starter at relay, ok. Changed both power cables, cleaned all ground connections and tightened. Changed Ignition switch. No crank. Found a high tech small shop. They spent a couple hours. They had a GM Instructor buddy who brought some cool (high tech gm troubleshooting tools). They found Ohm issues on the common computer BUSS. (Grounding out or shorting out). Then ended up Tracing it to a harness going to the trans (in the bundle it self). The trans connector was good. They re insulated / replaced the common computer buss (high side) wire in the bundle from the transmission to the ECU or TCU.
Problem solved.
They only way to see it was to have a breakout box, watch the ohms and see them go crazy when they shook the harness.
