7 blown fuses and counting

Vehicle:  1990 Jeep Cherokee

Deck: Pioneer

Problem:  Thought I would surpirise my gf for Xmas by replacing her crappy old deck with a new shiny one.  A previous owner has cut out the wiring harness in the dash to accomodate the old crappy deck.  I started by disconnecting the battery, identifying/connecting the constant & switched power, connecting the ground, then reconnecting the battery to see if it works before tackling the speaker wires. 

Each time I reconnect the battery, one of three fuses blow; "Dome" - which I assume if the switched power circuit, "Radio" - I assume is the constant, or the little fuse on the deck itself. 

What am I doing wrong?

Thank you for your replies. 

Is it possible the fuses were blowing because I hadnt yet connected the speaker wires? 

Also, when I pulled out the old deck, there was this apparatus which I've never seen before:

[URL=https://imageshack.us][IMG]https://img235.imageshack.us/img235/901/gggul8.png[/IMG][/URL]

Is this necessary?

No, it has nothing to do with speaker wires, it has to do with either he radio is bad or you are not connecting it properly.

The device in your image is a filter.  If one is required for your new radio it will have one as part of the wiring harness.

Follow the instructions in the link supplied by the12volt, and if this is how your system is connected it is defective.

The dome light is your constant 12vdc wire (because dome lights work when the igniton is off)

The radio is your switched power lead.

If you have access to a volt meter recheck all the wiring.  If you don't have a volt meter then I would suggest taking it to someone who has the right tools for the job.

If you really want to fix it yourself though, wihtout the proper tools What I would do, is remove the radio from the vehicle and connect it directly to the battery of the vehicle THROUGH the fuses in the wiring harness.  If there are no fuses in the wiring harness then use a 5A fuse on the constant wire and a 10A fuse on the switched wire. 

If you pop either fuse at that point then you know the radio is bad.  If the radio comes on then you know you've got it wired wrong.  Under NO circumstances should you connect the radio directly to the battery with no inline fuses.  You also need to make sure the metal case on the radio doesn't come anywhere near the positive terminal on the battery.

On second thought, unless you know what you're doing I wouldn't do what i explained, it could cause major damage to the car or radio, and possible even hurt you if you arn't careful.

Thanks for all the advice.  I exchanged the deck for a new one, and installed it easily. 

One minor hiccup though.  I think i may have crossed the Dimmer and Illumination wires.  The light which light up the dash console (speedometer, fuel gauge, etc) no longer work.  I also noticed the clock, which normally dims when you turn on the headlights, turns off completely when I turn on the headlights now. 

I have the illumination from the deck hooked up to the illumination wire in the truck (at least according to the wiring diagram)....would connecting it to the Dimmer wire remedy this?