Hi everyone.

I think this should be straightforward, but I'm new to these and could use some help.

Last Saturday, I went out for a drive and everything was fine. Last Sunday, the thing wouldn't start. There's no spark on any of the cylinders. So I checked the coil: the negative terminal has pulsing ground while cranking, but the positive terminal has no voltage on it when the ignition is set to "On." So my first impulse was to check the ignition switch; I'm talking about the one behind the lock cylinder with blue and black/blue wires. I pulled it and and it looks and tests fine.

Is there anything else between the ignition switch and the positive terminal on the ignition coil that I should investigate?

Thanks!

 

Check your auto shut down relay. Pcm tells the relay to turn on. Power then comes from it and the pcm. Does you fuel pump prime? They are both on the same circuit.

 

Turning the ignition switch to "On" does seem to make a sound consistent with a fuel pump priming.
Is the ASD relay one of the ones along the driver side fender? And the PCM is also in the fender at the very front?

 

Update: found, pulled, and bench-tested the ASD relay. Tested out of spec. Replaced it for $12, and we're back in business!

Thank you!

 

Developing:
Replaced the ASD, ran like a champ. For two days. Go to start it up today, and I've got no spark again. After a quick round of testing, isolated the ASD as the problem. Replaced it (again); runs like a champ (again).

Odd. Hopefully the truck isn't killing the relay on me.

 

Stalled in traffic today. Fixed by replacing the ASD. Again.
Not sure what to make of this.