Looking for insight to troubleshooting a new (to me) problem on my 2002 Dak 5.9L...

Yesterday afternoon when I went to start my truck, the engine started to turn over and then everything completely died. The truck now has no electrical power.

From the way it happened, I am thinking either a fuse or computer went on it--the truck ran fine 10 hours earlier when I drove in to work. I have ruled out the battery due to the fact that the engine originally turned over before the electrical power went out (and the battery won't go down to 100% drained instantly--there are no lights, and the power locks don't work either). I looked into the fuse box under the hood and didn't see any blown fuses. Weather-wise, it was cool and rainy, so high humidity (and I accidentally left my windshield wipers on in the morning, so they came on when I tried to start the car). Additionally, a couple of months ago I had to replace the ECU since the engine would occasionally cut out or not start, but at least then there was power to the cab.

Has anyone experienced this before? Looking for any insight before having the truck towed from my office parking lot, and want to determine if it is towed home or to a shop.

Thanks in advance!

 

Do you get 12 volts to the power outlet (NOT cig lighter) under the HVAC controls? It should be directly connected to the battery primary harness via the dash-side fuse panel.

Having the CTM, cluster, and PCM all go kaput at once is....interesting to say the least.

 

Neither the PCM nor the CTM will keep it from cranking. Power from the ignition switch goes through a relay in the PDC (under the hood) and then to the starter motor solenoid.

There's a 10 amp fuse in the junction box (side of dash) for the ignition relay. There's a 50 amp fusible link in the PDC for the solenoid.

Make sure the battery cables are clean and tight. They can corrode under the plastic insulation and look great but have no connectivity. Checking the power outlets is a good way to see if you have power like Magnet said.

The lighting is run by the CTM and without the proper voltage and current won't work. It's not like "older vehicles."
Also check all grounds.

Don't be surprised if the battery did die. They can fail quickly and fast. Get it load tested if you have any doubts.

 

Thanks for the input! There is a little corrosion on one of the posts, so I will try with clearing that off. Battery shows a 12.5 amp charge, so it does have power, however I wasn't getting any reading out of the lighter outlet.

Will bring a couple of metal brushes to try the post cleaning tomorrow. Fingers crossed!

 

Let's resolve this first.

Check the power outlet fuse on the side of the dash. Check fuses in the PDC. The power outlet ALWAYS has power. If it's dead and fuses are good, then there is a broken wire somewhere, and finding that will be your starting point.

 

Working through the checklist of easy things first, fuses are good and the battery posts are not bad (current to the ends of the wires just past the battery posts).

So, that leads to a problem in the wiring. Dumb question, but is there an in-line fuse in the wiring harness? I am getting a little caught-up in that the engine had turned over and wipers started just before everything died. Maybe the ground connection went bad all of a sudden?

Not sure if it means anything, but the driver's side lockset won't turn either, as though it is jammed--the lock can easily be open from inside though.

Thanks again for the insights! I think the next question will be whether to have it towed home to try and figure out, or to the shop for them to figure it out...

 

Check for power at the PDC, the fuse block under the hood, to a clean ground.

The cables themselves can fail internally and "appear" to be in good condition or you might have a bad ground.

There are no fusible links to the PDC. There are fuses in the PDC for the major circuits.

Try the brake lights. They bypass everything but the PDC, on a 20 amp fuse.

You can still have a bad battery. Measure the voltage while applying the brakes. It may show "volts" but have no "amps" behind it.

 

Okay, so no brake lights either... Also should correct myself--voltage on the battery is okay when measuring post-to-post, but if I ground of off the inner fender, the voltage is in the flat range. Measuring off the PDC post gives the same results as the battery post.

Could these readings lead to zero power being fed to "constant power" locations in the truck (i.e. brake lights and cigarette lighter)?

 

Yes to your question.

Measuring "post-to-post" does nothing but tell us the surface charge of the battery. You could have a bad cable, either positive or negative, or a bad ground or other connection.

Set your meter to volts and measure from the negative battery terminal to a clean ground. It should read nothing. Any reading means you have a bad ground. Your measuring "voltage drop" here.

Also measure from the positive battery terminal to the positive terminal connections at the PDC. Again, it should read nothing.

It sounds like you have a bad ground.

 

Cool, thanks again! I will check that out. Will also load test the battery this weekend.