Car Stereos: 1998 Jeep Grand Cherokee radio has no power., jeep grand cherokee, correct colours

Question
QUESTION: Hello Justin,

We removed the factory stereo and went to install an aftermarket Kenwood
238, however we are getting absolutely no power to the radio.  We connected
both the red and yellow wires and the ground but we are just not getting any
power.  How can we fix this, we checked the fuse both on the radio unit and
the radio fuse in the car and they are both fine.  Please help!

ANSWER: Hi Hector,

Did you use an aftermarket wire harness before connecting the wires?

I ask because the Jeep may not (and if I remember correctly from the Jeep installs I've done, does not) have standard colours, so you may not have connected the correct colours.

If you did buy an aftermarket harness, then this shouldn't be an issue because it will be standard colours.  Next, test the connections with a multimeter (you can get a cheap one from a local hardware store for ~$10 if you don't have one already.)

There should be ~12V on the yellow to black all the time, and ~12V on the red to black when the car is in accessory mode or on.  Ensure you're getting power that far first.

If you are getting power that far, but the deck does not turn on when plugged in, test the fuses with the multimeter (there should be 0ohms resistance across the two terminals on the fuse).  Some fuses LOOK OK, but are not.

---------- FOLLOW-UP ----------

QUESTION: Hey Justin,

I checked the voltage on both wires, the red is fine and shows power, the yellow however shows nothing.  We checked the fuses and they are all good.  Is there a way to maybe replace the yellow wire easily?  What else do you think could be wrong?

Answer
Hi Hector,

Actually, the software acted weirdly, and I mis-clicked.  I meant to click on 'answer this question', but their javascript autosubmitted the form when I clicked the 'homework' button.  It was completely unintentional, and I sent a message after that asking if you got my actual reply because I had given more information but it was still showing up in my 'pending questions' queue.

So, all in all, sorry about that, hopefully you'll at least get this one.

Justin