No power to Head unit

I have a new Jvc kd-s580 head unit and i cannot get it to work in an 89' pontiac firebird.  Im positive its not the head unit, and i know its not shorted.  My old after the market head unit works fine when i reconnect it.  It gets no power whatsoever and im positive that the ground, 12v batt, and acc are correctly connected.  I have installed head units before and never ran into this problem, which makes me think its the car.  I just cant figure out why the cd reciever wont work and the old tape deck will.  Please help.

Steve

How are you aconnecting the wires from the JVC to the factory harness ? If you are using an adaptor plug, there should be no problem... just hook up the correct wires to the colors of the JVC. Here is the pinout diagram for the 89 Pontiac:

https://www.velocitymotorsport.com/Pontiac_Car_Audio_Wire_Harness_Identification_Charts.doc

Check the fuse in the back of the deck or on the power wire to make sure that the fuses are not blow. Also check the fuse for the radio on the car as well. Post your results

I checked the fuses and they are all in good shape.  One thing i did notice though is that on the fuse box where "radio" is written there are two different arrows.  One arrow points to the 10a red fuse, and the other arrow points to an empty space that would hold a larger almost box like fuse.  Do you think that for this new head unit that has a 15a fuse in the back that i need to put a fuse in the empty slot?  The old head unit worked with just the 10a, but that didnt have a fuse in the head unit itself, only in the power wires.

Diesel, ill let you know when i get it.  It would be great if you could do the same.

Try running a new wire for the 12 volt ignition and the constant from the fuse box. Remove the OEM ground and find a new one. The deck should work after this.... if it does not, the deck is warranty repair for someone.

I agree with velocity motors, run new power wires to the unit. Last week I installed a deck in to a ford laser and it worked for about 5 minutes then just stopped. We checked the wiring and it worked again. Then stopped. The problem was bad factory wiring, we fitted new wiring to the fuse box and it is working fine.

(I hate cars)

How do i connect to the fuse box?

alright Lama....if you're still looking for info....here you go....

I don't usually go to the fusebox...but that's my preference...I go to the ignition harness....

get a DMM ( digital multimeter) go to the igniton harness, and find the wire that reads 12V or around there at all times...( it will very depending on how much voltage is in your battery )....switch teh key to all the positions and make sure that it stays around 12V at all times...this will be your 12V constant for the radio...

Next turn the key to the run positon and find the wire that gives you 12V again..when you do turn it off...the wire will lose power if it's right...if it does, this will be your turn on...for the radio...

run the wires to you deck...there you go...for getting a good ground...look under the dash, there's usually a place there that already has a factory ground...or you could make your own.....make sure its bare metal and it's a good ground...test with a DMM....but one lead where you wanna ground it, and put another to a 12V constant....if you get a full 12V's it's good....