Commodore electrical fault

Hi,

I have a VN commodore with some electrical trouble. It all started way
back when I had my airconditioner regassed. When I went to collect it
from the auto-elec he said that he regassed the airconditioner, but it
wasn't engaging. He said it engaged when he brided it directly to the
battery. So, he charged me for the regass that wasn't required and I
was on my way.. mumbling under my breath.

Being a hot summer I decided to run a wire directly from the battery to
the air con. When I started driving, then engine seemed to be working
quite hard, almost as if the air conditioner was seizing. When I
pulled up a few miles down the road, a heap of liquid was pouring out
from under the engine. I didn't stop to investigate further. The next
morning the battery was completely flat and I removed the wire bridging
the battery and the air con.

>From this point, the car began to overheat. It was fine at high speed,
though through the city it would boil. I put it down to the cooling
system needing flushing and kept along my merry way. Recently I had a
mechanic look at the car and he said that the thero fan wasn't kicking
in and that's why it was overheating. He said to get me out of trouble
he would bridge the relay under the bonnet with a bit of wire, but the
fan would run whenever the ignition was on. Yet again, being too busy
to properly address the issue, I continued to drive the car.

I have no idea when, but at some stage the thermo fan stopped running,
possibly around the same time the interior fan stopped running. Not
long after, I broke down from a flat battery.

I've since taken the car back to the mechanic and he sold me a new
battery. He also tried to bridge the relay again, but every time he
did, it blew the thermo-cooling fan fuse under the dash.

Now, my alternator light is coming on intermittently, the thermo fan
still doesn't run, and the headlights are pulsing with the engine on
high beam.

I have a access to a multimeter and some other equipment, but no
workshop manual. Can anyone suggest where I should start on this?

Cheers,