Thread: Electrical issues when wet

I have a 2004 Pontiac Grand Prix GT2 and have recently had electrical problems when it's rained and have gone through puddles. The first time it happened, I saw the lights on the dash flash and the radio turned off and back on. When I went to turn off the car, I turned the key off and pulled it out but the car was still running. I couldn't get it to shut off so I had to pull the battery cable. I left it disconnected and it seemed to reset everything.

Another problem happened to me today, I had driven it over the weekend in the rain and when I can out to it in the parking lot today, the lights were on. I tried to start it but it said the theft system was activated. I turned the key off and on a few times and it started. I left it outside and went to start it a few hours later but it wouldn't start. After trying to start, the whole electric system was flickering on and off without the key in it and under the hood I could hear the ignition relay clicking on and off quickly. I once again had to pull the battery cable and leave it disconnected to reset it all. Also, it had drained my battery so I had to get a jump.

Does anyone have any idea what it could be? Check engine light isn't on so I don't think there are any trouble codes.

Any help would be appreciated!!!

Thanks for the help negativeone13. I tried your suggestion of getting the coils and icm wet last night in the dark but didn't see any kind of arching. What happened today, I left the battery unhooked overnight so that it wouldn't be drained again. I connected the battery today and it starts right up without any sign anything is wrong. When I shut it off is when the problem occurs. As soon as I turn the key off, the dash lights back up, engine light is on, starting disabled due to security light is on and the the power door unlock sometimes doesn't work. I repeated this process several times today seeing if I could get anything to change. When I reconnect the battery, the trunk also sometimes pops open.

Does this sound more like a bcm problem because all the other power options are acting strange too? Or does the icm affect everything? I don't have time to take out the icm and go get it checked so I guess I will have to wait until I get the time to do it. Is there anyway to check the bcm? Also, can you swap those out or do you have to get a new one programmed at the dealer?

Again thanks for your expertise and on a college budget trying to avoid spending the big bucks at the dealer!