What fuse do i replace for the ac on a 2006 325i/

How did you hook up the inline fuse to compressor and ground to compress ? Ground what ? Right at the clutch coil ? You have to be hooking it up wrong . The compressor can't cause the clutch coil to short or blow the fuse , even if the compressor were seized up . An before that would have the serpentine belt would burn up , squealing noise. applying B+ voltage in the relay socket ,pin 30 to pin 87 will engage the compressor clutch . If the fuse blows the wiring from the relay to the compressor clutch is shorted to ground . Look for rubbed through wiring harness .

A fuse blows when an excessive amount of current is flowing through the protected wiring. Only parts using electricity in AC are the clutch and fan. Use an ammeter to identify which is the culprit and replace defective part.

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.

CHECK AC COMPRESSOR CLUTCH COIL WIRE CONNECTOR HOOK UP.IF AC COMPRESSOR CLUTCH COIL WIRE CONNECTOR HOOK UP WRONG OR WIRE HAS A SHORT IT WILL BLOW THE ECM FUSE AND AC COMPRESSOR FUSE.CHECK FUSES AND AC COMPRESSOR WIRES.

it sounds to me like a AC resistor issue i have a beemer that did that same thing to me and it turn out that it was my ac resistor it would burn out my 30 amp ac fuse in 2 to 3 minutes usually when the resistors in a circuit break they tend to burn out the fuses as a warning. easy way to find out is by putting in a new fuse and after a minute go touch the negative lead on you battery if the cable is really hot then there's a short in the circuit or in the case of your ac it would be a broken resistor.
http://www.oreillyauto.com/site/c/search/Blower+Motor+Resistor/02627/C0331.oap?make=Ford&model=Mustang&year=1995&vi=1134166
there simple to get and simple to replace.

The AC clutch is passenger compartment fuse # 5. This is the fuse for the circuit through the function selector switch to the AC pressure cut off switch & the AC pressure cycling switch.

The engine compartment fuse # 23 & 3 control the WOT ( wide Open Throttle ) relay to the AC clutch diode & AC compressor clutch solenoid.

could be AC compressor clutch shorting out.try disconnecting AC compressor electrical connector and see if fuse still blows.

UNPLUG THE A/C CONNETOR ON THE A/C COMMPRESOR. REPLACE THE FUSE AND TURN ON THE SWITCH. FUSE OK . REPLACE THE COMMPRESSOR AND THE RECIVER DRIER.

I would guess that your AC compresser clutch is shorted out. Try this: Look down into the area where the compresser is, and unplug the wire going to it. Replace the fuse, and try the switch. If the fuse does not blow, you need an AC clutch assembly. Let me know what you find out.
Hope this helps.

The fuse for the radio/CD/DVD is seperate from the AC/Heat. Open fuse box under hood on right. follow fuse schematic to ac fuse position (note there are two so if not one, then it is the other) use the fuse puller that is in the fuse box, then replace the fuse. Good luck.