Took my hood off to paint it two days ago, I covered the engine bay with plastic drop cloth to protect from potential rain. While painting my hood in the garage I noticed it started to rain so I looked at the truck and saw the drop cloth had blown over the cab and it was raining into the engine bay. I went out and recovered the engine bay. Yesterday after installing the hood I went to start the truck and it turned over a bit then stopped. Tried again and it was just rapid clicking from the starter. I was thinking maybe somehow the rain in the engine bay caused the battery to drain so I hooked up the battery charger. Went out this morning and when I turned the key the radio, fans, dash lights came on but the starter clicked once then stopped. Tried turning the key again and this time absolutely nothing happened. no dash lights, no fans, no radio. Switched batteries with my other car that I know is 100% charged, but nothing changed. Swapped out PCMs with another that I have and still nothing. When I turn the key nothing happens at all. What should I start checking? Thanks in advance!

 

First remove and clean your battery terminals / connections, then make sure they're installed very well.

Steve

 

Description is of a bad connection on a battery cable; I'd be checking BOTH ends of those cables. Then walk the cables to see if there's any "green rot" inside; with some attention, you can feel the difference between that and solid copper.

I have to ask why you swapped the PCM when it has nothing to do with the starter motor, the headlights, the horn, the radio, or the dash lights.

Symptoms are of the battery not being connected to the rest of the truck; so triple check ALL battery cable connections, BOTH ENDS.

If in doubt, replace the cables.

What year and motor is your truck?

RwP