Ok, so the vehicle has been unattended and off the charger for a few days now. Current battery voltage is 12.25v and at fuse 14 there's 10.5v with the key in the ON position. The fuse itself tested for continuity.

 

12.25v is a bit low.
12.6v is more better lol!
10.5v at fuse seems off???

 

Update: Started back at square one, since everything seemed to check out. I purchased a compression test kit, and even though I can feel some suction and compression when putting my palm over the spark plug/igniter hole, there isn't enough compression to even get the needle off the peg. I'll pull the valve cover back off and reinspect the timing chain, but it didn't seem worn last time I looked at it. And again, there's no abnormal sounds coming from the engine while cranking. I would think if the timing chain jumped a few teeth there would be some bad ju ju noises coming from the engine...?

What else could it be? Blown head gasket or complete failure of the rings? What would either of those have to do with the Serpentine belt failing?

 

Wow, we went from electrical problem to mechanical failure.

New question: Is your Vin # in the early 2006s for the 3.5L heads with improperly hardened valve seats? The S/Ns affected is any 2006 H3 lower than 287591 .... the first one started with 100,001, your truck build date will be Nov. 06 or earlier. Perhaps the head itself is bad.

Yes, you would hear it if the timing chain jumped or is jumping.

 

Yessir, the pitfalls of not having the right tool for the job. Could have saved so much headache. Oh well, at least I have it for next time now. The serial number is the last 6 digits, correct? This one end in: 206133, so it's in that range. Is there a test to perform, or is it just pull it apart and visually inspect it? But before we get carried away, why would this symptom suddenly appear? The vehicle was running fine until the Serpentine belt broke.

 

Cylinder 5 has 75 psi while cranking, all other cylinders read zero. Warped head?

 

Possible. When wifey was driving and the belt went, did she see what the temp was? No water pump for a while would overheat and you know the rest.

 

No, she didn't see the temp. But I justed pulled the cover back of to verify timing, and it looks like it jumped a tooth. How hard it that to fix with a chain? I've only ever done belts.

 

Well, the dark timing link does not line up with the mark on the sprocket. How many miles does it have on it?

Doing the front chain and tensioner (might as well look at the chain guide too while its apart) is possible w/o pulling the motor or trans.
Long and methodical job, no short cuts, and you need a couple special tools to do it. Click my link in blue.

3.5L Link for the engine manual