What would make my car heater fuse keep blowing, the ac come on full force and battery constantly dying?

NOT A RV ,right?
fuse # not told nor he AMPs rating. (hard job this)
on all cars, most fuse have not just one, load.
the fuse name is can only fit one name there, even up to 10 loads on 1 fuse. the service manual covers he wiring fully
scan the PCM so it can tell you what is shorted"? DTC errors.
F350 not superduty version (wild guess me)
I have trouble finding the 7.3L wiring in total.
ok found 35 pages of schematics on this. wowl
wish I knew fuse number F# that blew.
fuel heater means what?
Glow Plugs
intake induction heater MIAH
02 oxygen sensor heaters?
fuel filter bowl or water separator? heater?
fuel filter/water separator assembly., yes.
found it. I did, fuse 30/34 and 30 amps,in battery JB.
runs what you said and
waste gate solenoid. bingo shorted
+ 2 relay coils only 86 pins, I bet are not bad. PCM and IDM.
bingo

ip CLUSTER LAMPS,
BRAKES LAMP MUST NOT BE IGNORED, SCAN IT.
but see this....
BATTERY LAMP REALLY MEANS ALTERNATOR JUST DIED.
when that dies, battery discharges fast even 1hour long the battery does dead and will not make spark or crank it now bat dead.

forget the AC, AC shuts off to save you form stalling in traffic,
it delays the stall in truth , see that lamp go to autoshop or home fast.(batt lamP)
it is a blessing and the AC shuts off too, for engine overheat.
and if engine stalls (a no brain'er that, sorry)

The alternator is bad or its huge huge fuse blew in the huge engine bay box , 50 to 100amps comon size.
battery voltage is 13.3v to 15vdc, below that the alternator is dead.
check all fuse is wise now
I bet brakes are not bad ABS etc. or traction controls etc.
as battery goes dead one module after another goes dead(offline)
and most times spark is last, just making it home in time to fix it.
my all time record , drove for 1 full hour ALT ***** on the fly
and made it 1 bock from home, and coast the rest;.
other times less, done at least 5times in 50 years OTR.

it means you have a fiver

Underhood fuse box

Let's break this down.
1 Does the fuse blow when the heater is on, or just the AC?
Yes- Fan motor problem likely need new blower motor.
No- 2
2 Disconnect the AC compressor clutch wire. Remove the blown AC fuse, connect a multimeter across the sockets for the fuse, measure DC voltage across the two sockets with the AC switch, and Ignition switch ON. Is Battery voltage present?
Yes- The wiring harness has a short between the output of the AC switch and ground, likely a pinched harness.
No- The AC compressor clutch is shorted. Replace either the whole compressor or the clutch.

what about the heater. the a/c and heater share the same fan motor. If there is no force in the heater as well it may the the fan is not turning at full speed. should be able to hear the fan as well as feel the air from the ducts. another possibility is a blocked duct way. If you can hear the fan blowing full speed check the duct for obstructions.

ac clutch is going out

Replace the fan resistor located under dash near passenger side on the side of the heater box.

which fuse is blowing?

I have a 96 Intrepid, and none of the signal lights work. I tried replacing the fuse, but this did not remedy the problem. Could this be a loose connection?