Have a 92 Civic LX with 271,000 miles.
I changed out my heater core last weekend and when I put everything back together, I noticed my radio wouldn't come on at all(everything else came on fine, cig light, dash lights, heater controls, etc).
It's a non-stock radio(Sony radio).

This weekend....I checked out all the wires attached to the radio and they look fine.
Checked the radio fuse (under the dash)..looks fine...even replaced it just in case.
Checked the fuse in the back of the radio...looks fine..replaced that too...
Radio still won't come on...

Afterwards, I took the radio out and connected the black radio wire to the Negative(-) of the battery, and took the red and orange radio wires(tied them together) and connected them to the positive(+) of the battery, and the fuse on the back of the radio POPPED....TWICE(after replacing it with another fuse)!
Can anyone tell me what this means?

Thank you in advance!

 

If direct powering the radio is popping the radio's internal fuse the unit is no good. Time to replace.

EDIT: Just thought about it and you could try not powering one of the two wires you twisted together. One of those should be power and the other illumination. If you're lucky, there's an internal short in the illumination circuit that's causing the fuse to pop. If this is the case you wont get any back lighting but the radio should at least function until you can replace it.

EDIT2: Most Sony radios have a red wire for switched ignition power, an yellow wire for constant power, and an orange wire for illumination function.



http://sevimliler.biz/wp-content/upl...10-diagram.jpg

 

+1 During the test you need to be sure that none of the speaker wires or other wires from the radio are touching each other or anything metal. If that is the case, the radio has an internal short, replace it.

 

The ORANGE wire is +12VDC OUTPUT, not input like the RED and YELLOW wires. That's why it is blowing the fuse. You're welcome

 

Oops..sorry...I mean the yellow and red wire I tied together and connected to the positive of the battery...not orange.
But seems like I need a new radio anyway..along with a harness..since I basically just matched wire colors and connected my Sony radio like that from when I first brought it.
Thank you guys!

 

Update!

I got my new radio, and installed it but my new radio doesn't turn on at all......

I checked the fuses under the hood and in the car(Back up fuse and radio fuse)..and checked the fuse in the back of the radio itself....and replaced ALL those fuses just in case.....Radio still won't turn on.

I Double and triple checked all the color wires to make sure all the color match with the harness wires...taped them up....still won't turn on.....

Finally....I took my new radio and connected the Yellow and Red wire to the positive of the car battery and the Black to the Negative....and the radio came on.
I did the same thing with my OLD RADIO afterward..and that radio came on!

There's something wrong in the car....but not sure what.
I took out the cigg and pocket panel(lower center console) out and checked the wiring and connections......I don't notice any damage in the wires(nothing is pinched or exposed)..all connections are locked in tight.

I checked the harness with a test light at the red wire and yellow wire...the test light glowed red on both(not sure if my test light is just red, or red AND green)......I tested the connection before the harness on the same color wires...same result(glowed red).

I don't know what else to look for....
Should I go in DEEPER? That would mean I have to take out the dash AGAIN.

Let me know...Thank You in Advance!

BTW...my cigg lighter socket still works...

 

Check that the radio black wire is grounded when in the car. Many installers ground it directly rather than trust the car wiring.

Again if there are any shorts in the speaker wiring, either to each other or to ground, most radios will not power up.

 

Solved the issue of no power to the radio....
This is for future references....

I tested the yellow wire with a mulitmeter and got 12 volts....then I tested the red wire while I was grounded to the metal frame of the car and got 12 volts....
THEN I tested the same red wire and this time grounded it to black wire(Ground)....there was no voltage.

So there was a ground loose somewhere and I found it....it was a small connector behind the instrument cluster that attaches to a small metal tab that also is behind the cluster...See the attached photos.
Connected the connector, put everything back together and now radio has power!
Its incredible what you can forget when you take out the whole dash and unplug all those connectors, while removing so many components just to get to the heater core.

Thank you guys!