Lost power to multiple things while driving

[Beleakin]

I was driving my 2002 infiniti QX4 down the interstate while it was raining, and I suddenly lost A/C, the controls wouldnt even respond. The windows and the moon roof do not work, but the over head lights function, also automatic head lights died, but the brights still work. The 4WD light came on and does not go off. I am unable to switch from 2WD to 4WD.

I checked my belts, they are pretty worn, but still spinning. I checked the battery with the car off, it reads 12.9V, car on, 14.3V. The car will start up, I got to disable the gear lock, but I can put it in get and drive it.

The under carriage to my car broke off a few months back, could water splashing under the car cause multiple electronics to quit working? I mean half the car just does not work now.

I am not familiar with checking fuses, could multiple fuses blow at the same time?

I am desperate and appreciate any advice.

[Towncivilian]

Water could have gotten into some harnesses and caused shorts. Are your battery terminals tight and free of corrosion? It's certainly possible for multiple fuses to blow at the same time. I'd check the ones behind the driver coin tray first.

What do you mean by "under carriage" - do you mean the plastic splash guard that's under the engine? I don't think it's necessary, I've driven without it for 8 months or so in rainy Florida and never had any problems.

[Beleakin]

I checked all my fuses with a multimeter, and the battery and alternator check out. Im thinking some kind of relay has gone out, but I do not know which are which.

[Towncivilian]

There is a circuit breaker above the fuse box behind the driver coin tray, near the three blue relays. Do you think you can find it and reset it? I've never seen it so I don't know how you'd reset it - if it's just a button or if it's a switch.

[Beleakin]

I looked around around the blue relays and there was a hole that had a white thing inside it. I tried pressing it with a pen and it did nothing. I am not quite sure what I was looking at.

[Beleakin]

I am trying to figure it out, but I am clueless for the moment.

What could simultaneous knock out my a/c, power windows, moon roof, auto detect lamps, 2WD to 4WD switch, all at the same time.

I also have to use the unlock button to get the car out of park. This all happened suddenly while driving. I am trying to find a component that effects all those things.

[Towncivilian]

I think you should have your battery tested at the dealer or an auto parts store (it should be free either way; I believe they can also test your alternator). They are probably not related but it would not hurt to rule them out.

[Beleakin]

Ground wire... Had a buddy at work take a look at it, and it took him 10 minutes to replace the ground connection and everything works like magic. It was a ground wire he ran through the door. I wasn't watching him while he did it, I was working, but wow what an instant difference.

[Towncivilian]

Which ground wire was bad?