Local audio gurus?

[bssmith1220]

I recently bought a 04 cobra vert that has no sound from the radio at all except some crappy no bass sound from 2 speakers total in the rear. I found out that a previous owner had aftermarket subs, amp, and head unit in the car. Looks like all the stock stuff is in place now, just doesn't really work. So factory speakers, amps, and radio all look to be in place. Anyone have any tips on how to trouble shoot this? I don't want to spend a fortune on all new stuff, just the factory Mach 460 would be good enough if it worked. Any advice would be appreciated!

 

[rowapr]

if he had an aftermarket radio pull the radio out. he may have hacked up the stock wiring. remove the shifter knob, pull up shifter trim by placing fingers under plastic by the shift boot and pull up gently. remove the acc port plug. pull the vent trim by gently pulling it off starting at the bottom and working your way up. unplug 3 connectors at bottom of trim. pull the 2 7mm screws below the radio and slide out radio. (sorry if this is long some people have never done this.) there are 2 connectors 8 pin and 24 pin. both grey connectors if you have a 16 pin black connector that may be an issue.) check the wiring to see if it has been cut for the aftermarket harness and poorly reinstalled or not plugged in at all. the 8 pin is for the subs. because the subs dont seem to be working look at this first. if the plug appears modified check the colors to see if they match up. next drink a refreshing alcoholic beverage. if this looks ok on the surface lets do some power and ground testing. check the ground wire in the 24 pin plug, pin 13 that is black with a light green tracer (line). now check pin #1 that is violet with a light blue tracer for 12 volts. that is the end of the basic testing before we start unplugging components for shorts and ohm testing wires if those 2 check out. without a multi meter we can say this. i assume pin 1 has 12v with the radio powering up. before you remove the radio turn the car to the run position. the 2nd ground (same ground circuit as pin 13) for the radio is the case to the screws connecting it to the dash for ground. if the radio is screwed in and works unscrew it with the radio still powered up and carefully remove the radio and see if it turns off. if it does you may have a ground issue.

that is the super basic checks before you start getting into a pita job. but here is an educated guess on what is happening. most aftermarket radios use a harness on the 8 pin connector to convert to rca cables. this plug is either missing or unplugged or the adapter is still pugged in. this plug goes to the two amps in the trunk and those control the subs. the front tweeters in the door (music not bass) are very hard to find replacements for due to the size and may be removed or unplugged. you can access them by pulling the covers off by hand and checking if they are still in the door or take the screws out to check if they are plugged in. they may have extended the wires down the door to install a coaxial speaker. the radio has an internal amp for the tweeters front and rear and that is most likely why only your rears still work. so i dont think its a power ground issue but its always best to start there.

i should have started with this but check to make sure the bass isnt all the way down on the radio (bass button then button the right up or down ) and the front rear bias isnt set to rear (fade button then button to the left up or down).

 

[bssmith1220]

I pulled the radio out last night. Everything is plugged in, but you can see bare spots in the 24 pin connector wires(like someone had things tapped into several of them). The tweeters are still in the door, and that's where I ran out of time. All of the radio settings are ok, the front speakers (all 4) have zero sound and only rear lowers produce anything.

 

[rowapr]

try checking fuses 13 and 15 under the hood an fuses 6,9, 27 and 32 under the drivers side dash. also check the two grounds for the radio. one is black and the other is black with a green tracer. they share a common grounding point. check rear amp grounds too, black with green tracer. if those are all good we might be looking at a radio, wiring to speakers or speakers themselves. if we have confirmed power and ground to radio test the tweeters first. put probes to the orange/light green and light blue/ white wires and connect then to a known good speaker or a set of earbuds from an ipod or phone (put alligator clips to 3.5mm jack and the other end to wires). if you still have no sound it might be the radio and power and grounds should be rechecked before condemning the unit. if you have sound follow the wires fron the unit to make sure they are not cut. then check connectors. for the ds front there is one in the kick panel, behind the dash panel under the steering wheel and one in the door by the speaker. pull the ds front speaker out and test with known good radio. the subs in the rear are on one amp in the rear and the fronts are on the other for referance