03 Ex Charging System.
 

Good Day to All,

I am having some strange troubles with a 2003 Civic EX. The instrument cluster started first in that it would go in and out completely and all the warning lights would either stay on or flash and then go out and work normally for a while then the cycle would repeat. This went on for a couple days and then the odometer went out and stopped lighting up all together. I grabbed another cluster off Ebay and sent the old one out for repair so I could maintian correct mileage etc. Weird part is the new cluster does the same thing just not as badly.

I removed and cleaned the grounding point under the dash even though it looked great to begin with I sanded and cleaned it all up. I then began to suspect the charging system after reading some previous posts on here. So I took out the old voltmeter and measured 12.5VDC on the battery when the car was off. When the car is running it goes to about 19.2VDC at the battery. At the cigarette lighter I get the same 12.5 VDC when the car is off but I get a 14.7 - 15.1 and it does seem to vary a little more than I have ever seen on a car.

When I rev the engine a bit the gauges will go whacky and shutoff as if they are getting too much voltage and the car is no longer regulating it.

I wonder if the cluster gets a little too much voltage and it trips the bias circuits for the ights etc on the cluster electronics.

Anyone have any wiring diagram for the charging system of this car? I have read about load modules on the car and a seperate voltage regulator but need a diagram and some idea of how to trouble shoot these items before replacing the battery and alternator. I am also heading to a mechanic today to have the charging system checked out for general problems.

Thanks in advance for any help you can offer.:)

RE: 03 Ex Charging System.
 

your alternator is overcharging i have a 03 honda civic ex it had all the same problems but i made a mistake and brought it to the dealership they wanted 600 bucks to fix it