New Stereo Support - Constant 7V on ACC (4 Viewers)

[Slotosea]

My stereo ACC wire (red one) is getting 6V constantly and then jumping to 12V when the car is on. How do I troubleshoot?

I just wired in a new cheap stereo using a Metra Wiring Harness. To my own surprise, everything worked great right away! I could turn the cruiser on and off and the radio followed as well. The radio powered and kept memory, and the speakers functioned. Then I went to screw everything back up on the dash, and my radio came on without my keys in the ignition. I didn't make any sudden movements, just a bit of vibration from screwing in the air vent. Now, I can't turn the radio off. I checked behind the harness, and the yellow memory wire is getting constant 12V, and the red line is at 7V constantly and 12V when the car is on.

I also don't know if this is supposed to be like this, since I didn't check before installing. There is a small chance it is just a fault of my cheap new stereo. The cigarette lighter is also getting 6V constant and 12V when on. Ground is at 0V. I didn't get anywhere looking through the existing forums, so thanks for any help you can offer.

I have a 1996 HZJ75 Troopy with some interesting features from previous owners. This is my first time posting after having the rig for only a couple of months, hoping to make a better first post with pics and the rig description when the weather is good up here and the cruiser is in a bit better shape.

 

[Slotosea]

Update, I fiddled around again while checking the voltage of the ACC line. I didn't catch what it was, but SOMEHOW it fixed itself. Now the ACC has 0V off, and 12V on, so my new radio is working again. My new theory is there is another dash component with a bad wiring connection (clock? AC?) that is creating a 6V backfeed. Let me know if anyone else has experienced this and can help.

I am going to call it quits tomorrow. But this weekend I can take more of the dashboard off to disconnect other dash components completely to see if I can recreate/fix the issue.

 

[jblueridge]

What year and which vehicle?
Cig lighter is always powered on too I think.

 

[Slotosea]

1996 HZJ75 Troop Carrier. I'll check what the Cig lighter voltage is now that I fixed the ACC line somehow.

 

[jblueridge]

My 1988 does not have a constant-on memory wire. I made a complicated system to work around that.
I learned that the yellow memory wire on the stereo is also the main power connection and the red “power” wire runs the off/on switch. Not knowing that caused my earliest work arounds to fail.

 

[Slotosea]

Fixed! Hopefully, I can help someone else who is looking through forums in the future with a similar problem. The original digital clock was broken but still connected. It appears the clock was shorted, creating a constant live ACC wire. I disconnected the clock, and the stereo has been working fine since. I'll see if I can fix the clock, install a new clock, or find a different use for the clock space since my stereo has the time on it anyways.

I also made a fun boot logo from a drawing my friend made for me, video below Message me and I can share the photo if anyone wants it!



So check the voltage while disconnecting all of your accessories that also have an ACC wire and a memory wire, one of them may be shorting the memory and ACC line.

 

[jblueridge]

I found a clock out of a 60 Series and swapped it into the 74’s metal housing/box.
Clock guts were the same.