I am new to this so please help me in any way. I have a 02 Dodge Ram 1500 5.9. I got in it and cranked it up and as soon as I turned on my headlights, The engine died and I lost power to everything. The red led light on the dash started to flash like the battery was dead but the engine still turns over but will not crank. I still do not have power to anything at all but the engine will turn over with the ignition swicth. Please let me know what could be wrong. Thanks in advance.

 

Battery is my first and second guess.

 

Wait. So the engine is attempts to crank over or just clicking?

 

The battery is only a yaer old and yes the engine turns over like it wants to crank but will not fire, but nothing else on the truck, headlights, cab lights or anything else will work.

 

My suggestion is start from scratch. If it turns over then you can eliminate the battery.

Check the fuses for the lights and even no fire. After fuses check for fire on the cylinders, then check for fuel at the rail.

Can go further from there.

 

If I'm not mistaken, there is a feature on the truck which allows the computer to disable the lights and radio and everything if the battery falls below a certain voltage mainly for if you are using it for light or using the radio to make sure it will have enough power to turn over the starter one last time. I know mine did the same thing when the battery died in it a few years back. Start with having your battery charged and tested to be sure. Local auto parts store should do it for free. If the battery is only a year old and it's the problem, it should be under warranty so it's a free fix.

 

Second suggestion is the computer for the body, controls lights, alarm, door locks and stuff like that, located with the trans computer and the PCM. I know mine has 3. Engine-trans-and body. Mine is an 03, 5.7L tho. not sure about the 5.9

 

The hot line splits.. its conceivable that the post that splits power has a bad connection with the harness that powers the chassis, but clean connection to the starter..

Take all connections off one by one, cleaning and using petroleum jelly on each (it WILL NOT corrode with pj on them).. make sure the grounds are solid everywhere; pay close attention to the PCM plugs/harness (passenger firewall, its the block looking thing).. also pay attention to altenator connections..

A truck will not run without juice or ground.. its that simple.. that sounds like what is happening to you..

 

Btw: your 02 5.9 has only one computer/pcm..

 

Thanks for all your help. I have found the problem. It was a bad ground cable to the frame. Something that simple causes alot of problems. Thanks again for all your help.