4.7 SLT Issue

[vantage08]

Well I've never had an issue with washing my engine untill now. I washed my 4.7 SLT dakotas engine yesterday and now it won't turn over. It started initally with no issue directly after. I shut it off then detailed it. A few hours later I go to start it back up again and it doesn't turn over. I try it again and then it starts. I checked the fuse box to see if there was water in it but it was bone dry. I then revved it up and the lights dimmed. Almost like the battery was going on it but it's a new battery. So I took it for a drive to heat up the engine to help dry it out. I came to a stop for a minute and the lights started to dim. Then they came back up to full strength. I came up and parked in in a spot where if it didn't start back up again, I could take the pontiac to work if I have to. Well, I went to start it up last night to head to Miller's Ale House and it woulnd't turn over at all! THe dash lights would flash but wouldn't turn over. So I took the pontiac. I tried it again this morning with no luck. It didn't help that it rained last night. I'm going to unplug the PCM to see if there's any water in it when I get home. Maybe take out the modular plugs to see if water is in there. I def need my truck! Anybody have any ideas? Like I said before, I've never had an issue with washing engines.
Brent