Weird radio electrical issues

[Big Dan]

Long story short, my radio died (I thought). So, I bought a new one. New one wouldn't turn on.

 

Fuse for the radio was fine, but upon further inspection, the actual contact on the box was broken. I ran a new line from the an open accessory slot and tested for power..it receives power. However, neither radio will turn on.

 

Any one had an issue like this?

[HOrnbrod]

Radio chassis ground hooked up?

[Big Dan]

I wasn't sure where the ground wire (from the original wiring) ran to, so I just ran a new wire from the radio to ground. No luck.

[Big Dan]

With that said, I still may have not been getting a good ground. The FSM does not show where the ground is located. Does anyone know?

[gogmorgo]

It's the spade terminal to the right of the main connector. Can't speak to where exactly the wire goes from there, but I suspect it's the main dash ground. Should be pretty easy to check for continuity.

[Lee21490]

They usually have two power lines, One constant & another that only receives power when the key is turned on.

 

Have you checked the second power line?

[Big Dan]

Yes,the constant receives power as normal. I ran a new line for the ignition power and a new line for the ground. Still nothing.

 

I'm at a loss as to where to go.

[zomeizter]

If your 12v constant, 12v ignition and ground are good, your radios are bad...

[Marine1Texas]

one thing that will not allow the radio to come on for some after market radios is if any speaker lines are grounded. On many radio's they use 2 types of ground, a permeant ground, and a ground that is added thru the antenna cable. I have had radio's in the past that draw high amps use the antenna cable for 75% of the ground....

[tugalo]

under the dash, just forward of your left knee, just above the brake release.

[Big Dan]

It may be my laziness and if so, I'll have to wait until tomorrow.

I originally attempted to wire the new radio with just the constant, ignition and ground to ensure it would turn on before I wired everything else. I did not have the antenna plugged in.

I just now plugged in the antenna, no change.

 

With that said, the speaker wires are currently connected from the speakers to electric tape. If you theory is correct and they are still grounded (by being wrapped in tape) , I'll wire them up tomorrow and give it a go.

This is frustrating.

[Big Dan]

under the dash, just forward of your left knee, just above the brake release.

I found it, thank you. I'll run the ground to that location in my attempts tomorrow.

[Big Dan]

Well, wired everything up.  Constant and ignition voltage is good as is the ground.  So, I guess the new head unit is dead on arrival.  Ill return and go from there.

[Big Dan]

I RMAd the old head unit. Still no power up with the new unit. Ive tested the ground, constant and ignition at the harness and everything is good to go.

 

After digging around the antenna to make sure everything was good to go with that, I found the following dangling. Someone mentioned that the antenna played a part in the ground. I can't find where exactly it plugs in. Any help would be appreciated.

 

[Big Dan]

Double post

 

Edit - to clarify the above post, where does the antenna wire connect into the physical antenna? That wire is dangling by the passenger side door

[tugalo]

that looks like the coax from the antenna that should plug into the back of the radio.  you can always to to the junkyard and get an antenna and a lead from almost any cherokee and replace the entire unit.....

 

the little square connector looks like the connector for the footwell courtesy light.

[Big Dan]

Who knows, I might have to.

 

That coax for the plug into the back of the radio is in the correct location (where the radio is).  That line ran to the dangling end, however.  I assumed that the dangling coax would hook into the antenna somewhere.

[Gene]

Hi Dan,

 

All of this makes no sense.

 

Try this: take one of the radios, go to the battery under the hood. Run one wire from the negative terminal on the battery, over to the radio ground. Run two wires from the positive terminal, one to the always hot, one to the hot with ignition on.

 

If the radio powers up, then there's something going on with the wiring under the dash.

 

If it does not, then the radio is defective.

 

I can't imagine that the antenna connection is the only ground connection to the radio. I don't think the antenna being plugged in should make any difference.

 

I can't comment on the need for the speaker to be connected, I've never run into this. To really make the "direct to battery" test complete, you might have to temporarily connect a speaker in.

 

Good luck!

 

Gene

[Rockfrog]

Test power at the red/gold lead, then test when the radio is turned on. I had a similar issue where I had voltage, but not enough to run the clock and radio. Could only get the OR the radio to work at one point. Given my fuse box was hacked by the PO I pulled power from the lighter circuit for the radio as a work around.

I was seeing only 5v on that circuit at times.

Haven't had an issue since, but also picked up a new (to me) 88 fuse box/dash harness to mess with another day and solve that and a few other issues the PO left me to fend with.

[Big Dan]

 

Hi Dan,

 

All of this makes no sense.

 

Try this: take one of the radios, go to the battery under the hood. Run one wire from the negative terminal on the battery, over to the radio ground. Run two wires from the positive terminal, one to the always hot, one to the hot with ignition on.

 

If the radio powers up, then there's something going on with the wiring under the dash.

 

If it does not, then the radio is defective.

 

I can't imagine that the antenna connection is the only ground connection to the radio. I don't think the antenna being plugged in should make any difference.

 

I can't comment on the need for the speaker to be connected, I've never run into this. To really make the "direct to battery" test complete, you might have to temporarily connect a speaker in.

 

Good luck!

 

Gene

Gene,

 

This worked.. On both radios. So, I'm obviously doing something wrong underneath the dash. What doesn't make sense, however, is the voltage at the harness is correct -a little under 14 with the vehicle running.

 

Is it possible I'm not supplying enough amperage? As I stated previously, the radio contacts on the fuse block were broken, so I am running the ignition line from the clock's plug in (on the fuse block).

[Gene]

Good troubleshooting so far!

 

Next question: Is it the hot, or the ground, under the dash?  May be a bad ground. Are you measuring voltage to the ground wire, or to another ground point?

 

As Rockfrog said, you may be getting voltage (or ground) under the very light load of a voltmeter. But the heavier load of the radio is not supported. This can be a problem on either hot side, or ground side.

 

Can you try a test light, rather than a gauge?

 

Gene

[Big Dan]

Well, your alls help did it. Thank you.

 

The constant was getting voltage, but apparently the was an issue with the wire under the dash somewhere. I ran a new constant wire and it the radio starts up perfectly.

[tugalo]

Had a Mopar headlight that would not work onetime.....it had the correct voltage, but the wiring had been over crimped and could not supply enough AMPS to light the light. Drove me crazy cause it had the voltage.....you could have a similar problem.
 

[Big Dan]

I do believe that's what it was. Thanks again for everyone's help.

[Gene]

Good work Dan!

 

Gene