I have a 1997 Civic DX. When the car is running the volt meter I have show only 12.8 volts. When all lights , heater, rear defrost, and wipers are on it goes down to around 11.9-12.2 volts. I changed the altenator. Changed the fuse box to replace the load sensor. It still has the problem. Any ideas?

 

have you checked battery and the battery cables?

 

check battery and cables...
no corrosion on terminals right..

 

new battery and cables are nice and clean

 

How is the tension on the alternator belt?

 

It has a little bit of give to it.

 

See how much give, if we're talking give to the point that it's slipping...then it's not gonna turn and charge like it should. Maybe tighten it a bit.

 

Check the vss/alt fuse under the dash. Also check the alt plug for corrosion and fit. I would use some dielectric grease on it as well.

 

2nd vote for check that VSS/ALT fuse. I think it's #15 if memory serves.

Had the same problem with my wife's 98 LX. Ended up being a wire in a harness way up under the intake mani that had rubbed so long that the insulation was gone and was shorting to ground, blowing that fuse every time. A little heat shrink and taping the harness up to keep it from rubbing and we were good to go.