POWER TO COIL PACK BUT NO POWER FROM IGNITION CONTROL

Harold Bisset · May 10

Hi, I have a 2002 GMC Sierra 1500HD with a 5.3L

I have a problem with getting the spark control to the ignition coil on cylinder number 3

I tested power to the coil (good) the truck runs, there is a misfire on cylinder number 3

Truck has new coil packs, spark plugs, and wires.

I do not have "spark" from the computer to tell the coil pack to fire, does anyone know which wire on the harness where it plugs into the ECM is the control for the cylinder number 3 coil pack? That way I can rule out a bad ECM and find the break in the wire.

Gagliano7 · May 12

https://images.app.goo.gl/52CRYF6XWbfGWXiw6

Harold Bisset · May 12

2 hours ago, Gagliano7 said:

https://images.app.goo.gl/52CRYF6XWbfGWXiw6

This is the incorrect diagram, this is a distributor-less system. I will post a picture of the correct one later. I purchased a Hanes manual and traced the wiring that way and found a break in the wire behind the coil pack mounting bracket.