AC fuse blows, then voltage drops to 12.3v

[RidgeRunner]

Got a doozy of an electrical gremlin for you guys to help me figure out...

First, the AC fuse blew, leaving me without cold air... At this point, the voltage drops to about 12.3v. Replaced the fuse, battery voltage was back to normal. About a week later, it did it again. I verified its behavior by starting the car, reading 12.3v, shutting it down and replacing the fuse, restarting it, and finding that it indeed reads about 14.8v afterwards.

1. What could be causing the fuse to blow? The schematics in a haynes manual show the blower, AC clutch, and the relay for the cooling fan running off that fuse. And how is this affecting #2?

2. Here's the real doozie - after that fuse is blown, why in the shit does the battery voltage drop so much? (Voltage reads low both at the cluster, and at a 2-way VHF radio fed from the stereo wiring right off the battery.)

It acts almost like the alternator is charging the battery THROUGH the AC fuse... Electrically, I just don't understand how this could happen, but obviously something of the sort is indeed happening. I just need to figure out where to look for the problem.

[Juglenaut]

What have you done to the car in the last 6 months?
Added anything, modded anything, anything in or out...

[RidgeRunner]

What have you done to the car in the last 6 months?
Added anything, modded anything, anything in or out...

Added the aforementioned VHF radio, and a new Optima redtop battery. I think that's all... Alternator is probably less than a year old.

The radio simply taps into the audio system wiring with two wires, so I don't see that being an issue in any way.

[RidgeRunner]

This damn thing really puzzles me.

Tried measuring voltages at the battery and at the alternator... no difference between the two... both are 12.3ish when the AC fuse is blown, both are 14.8ish when the fuse is intact. Somehow, the alternator isn't charging when that fuse blows.

[gpse3400]

check the resistance of the A/C clutch coil.Verify the wiring isn't grounding out. THis also includes cheking out the inline Diode. Hey jon

[RidgeRunner]

hai lorenzo.
I'll check that AC clutch... but I've got bigger fish to fry right now. Starter seems to have died. I'm gonna kick myself hard if this turns out to be all related to one root cause. But it honest-to-goodness seems like a dead starter to me (grunt... click click click... battery still has good voltage, car push starts okay)

[RidgeRunner]

Update

Starter died, I replaced it with one from the u-pull-it.

I think I've ruled out the AC clutch as the cause of the fuse blowing - can't even turn the heat or vent/fan on without blowing the fuse. Blower motor is new, was changed during these problems - made no difference.

Need to get out there and trace wires, it looks like. Pull fuses and measure voltages too. See what's doing what.

[d.o.h.c]

check your fusiable links.