I just picked up my 2003 G35 6MT Coupe over the weekend. I've been going over the entire car considering it was in rough condition electrical wise.
the car has nothing aftermarket at all, nothing seems like it had been touched or replaced. Had a clean record with no accidents and my harness looks ok thus far.
The problem I'm facing is NONE of my gauges are working, nor is the back lighting coming on when I turn the lights on. I do however have indicator lights like the slip, battery, oil, etc lights turn on during the check phase. Also the headlight switch itself including blinker control does not work nor does the whipper control switch.
The clock spring looks ok and tested fine, figured if it was bad I wouldn't have any electrical at all to the dash anyways. I've gone through all of the fuses inside and out of the car. I've replaced both switches and the instrument cluster and still nothing... I'm down to either a simple calibration which I still dont see fixing the switches or possibly the ECU? Just looking for any tips or idea of what it could be that I might be missing before I jump to replacing the ECU.

 

^
My advice is before you start just replacing parts and guessing you should obtain a copy of the FSM for your vehicle and use a multimeter for testing thru the wiring harness to pin point where you are losing voltage.
There are hundreds of thousands of damaged flooded vehicles floating around and the corrosion that occurs in wiring takes time to show up and is sometimes difficult to pin point.
Was this vehicle originally purchased in your state or somewhere else. I assume you paid a cheap price so spend the $150 to have a dealer run a VIN and service history check for you.

Just my $.02

Good luck

Telcoman

 

I bought it from a dealer for $2000, I got an updated carfax on the car with the purchase. I was told this issue was on the vehicle before purchasing but couldn't beat the pricetag. Fortunately I'm not at the throwing parts at it yet, had spare parts from my 350z and old G35 sitting around for testers, that's why I'm asking before I start throwing lol. I've checked a fair amount of the harness what I've tested thus far has no issues. Going to try getting the wiring diagrams today. If it's not the harness though could it be a simple calibration or would this be more concerning as needing a BCU or the ECU?

How much more info can a dealer pull up than a carfax out of curiosity? Serious question, not trying to be a sarcastic *****, just wondering if it's about the same or not.

 

Dealership will usually pull multiple listings not just carfax if you ask them.

Honestly if all the fuses including the fusible link, IPDM, Junction Box J-B ALL have no blown fuses then it's likely a blown combination meter. You can test it though, can't remember the entire process but you can google it. Something like this, hold down the odometer button, turn the ignition to ON, push the odometer button 3 times and it will enter diagnostic mode. Then you can press/release the odometer button to test gauge operation, when you press they will all increase 25%, release and they all zero out again. If nothing moves it's a damaged combo meter.

Headlights is a little more tricky, I'd start at the headlight relay and fuse and see if maybe it's just blown, if you don't receive control power to the relay then the problem is LIKELY in the clockspring which is a common failure point on the G. Since you are also having wiper problems I'd highly suspect the clock spring.

 

Cleric670, appreciate that! I'm working on the cam sensors currently and found out whoever installed the only aftermarket part (down pipes) must have cut the connector for cam sensor 1 off. Current issue. Gauges are next if this doesn't correct anything. Appreciate the info again!