Car Stereo Fail
Thread Starter
Intermediate
Joined: Oct 2018
Posts: 39
Likes: 0
From: Jacksonville, FL
Car Stereo Fail
Hey!
I pulled an old car stereo, labeled my wires, and am setting up a wire harness for my new, bluetooth enabled one. When I wire up just the ignition power and ground, it won't power up (Yes, the ignition switch is turned to run). I tested the circuit with an incandescent bulb from the gauges I had lying around and the bulb lit. I decided to get formal and put a multimeter on it and got 12V. The fuse in the new stereo is good so, I thought tonight I'd try to reattach the old tape deck that I know worked to see it I could get it to come on.
Does anyone recognize the problem? I thought maybe I'd try running a new ground wire somewhere but, that doesn't make any sense, right? If the existing circuit is reading 12V the stereo ought to be able to use it just fine.
Also, the old stereo had fuses spliced into the wires. The ignition wire I think is stock so, not sure why the fuse was added and the constant wire was spliced into the cigarette lighter. When I checked the fuses under the dash, there was no fuse in the radio port. I'd like to replace it but, don't know what amperage it needs. Anyone here know the amperage the radio fuse socket calls for?
DISREGARD the fuse amperage part. I found the answer here. Looks like I need a 20AMP fuse.
Thanks for the help!
I pulled an old car stereo, labeled my wires, and am setting up a wire harness for my new, bluetooth enabled one. When I wire up just the ignition power and ground, it won't power up (Yes, the ignition switch is turned to run). I tested the circuit with an incandescent bulb from the gauges I had lying around and the bulb lit. I decided to get formal and put a multimeter on it and got 12V. The fuse in the new stereo is good so, I thought tonight I'd try to reattach the old tape deck that I know worked to see it I could get it to come on.
Does anyone recognize the problem? I thought maybe I'd try running a new ground wire somewhere but, that doesn't make any sense, right? If the existing circuit is reading 12V the stereo ought to be able to use it just fine.
Also, the old stereo had fuses spliced into the wires. The ignition wire I think is stock so, not sure why the fuse was added and the constant wire was spliced into the cigarette lighter. When I checked the fuses under the dash, there was no fuse in the radio port. I'd like to replace it but, don't know what amperage it needs. Anyone here know the amperage the radio fuse socket calls for?
DISREGARD the fuse amperage part. I found the answer here. Looks like I need a 20AMP fuse.
Thanks for the help!
Last edited by anonimitie; Nov 20, 2018 at 08:43 AM. Reason: Found part of the answer
Melting Slicks
Joined: Sep 2016
Posts: 3,004
Likes: 104
From: NC
New HU require 2 power wires, one for memory basically(constant power) and the other for main power(switched).
I would bench test the HU using a fuse of course and see what's going on.
The manual for the radio should have shown required wiring.
If it bench tests then at least you know the HU is good...
I would bench test the HU using a fuse of course and see what's going on.
The manual for the radio should have shown required wiring.
If it bench tests then at least you know the HU is good...
Thread Starter
Intermediate
Joined: Oct 2018
Posts: 39
Likes: 0
From: Jacksonville, FL
New HU require 2 power wires, one for memory basically(constant power) and the other for main power(switched).
I would bench test the HU using a fuse of course and see what's going on.
The manual for the radio should have shown required wiring.
If it bench tests then at least you know the HU is good...
I would bench test the HU using a fuse of course and see what's going on.
The manual for the radio should have shown required wiring.
If it bench tests then at least you know the HU is good...
Thread Starter
Intermediate
Joined: Oct 2018
Posts: 39
Likes: 0
From: Jacksonville, FL
Le Mans Master
Joined: May 2003
Posts: 8,877
Likes: 3,556
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
It used to be- 20 years ago- the constant power (yellow wire) was just to keep memory/clock- and pulled a small amount of power.
However -the yellow wire POWERS the radio totally these days- and can easily pull upwards to 10A.
The ignition source - red wire- JUST triggers the radio to come on- there is very little current draw (usually less then ½ amp)
So make sure you have a good clean source for power - or you are likely to get ignition/alternator noise.
Especially since new radios have USB inputs which are very susceptible to noise.
There's been several cases where going to the battery for both power and ground to the battery was required to get rid of the noise.
Richard
However -the yellow wire POWERS the radio totally these days- and can easily pull upwards to 10A.
The ignition source - red wire- JUST triggers the radio to come on- there is very little current draw (usually less then ½ amp)
So make sure you have a good clean source for power - or you are likely to get ignition/alternator noise.
Especially since new radios have USB inputs which are very susceptible to noise.
There's been several cases where going to the battery for both power and ground to the battery was required to get rid of the noise.
Richard
Thread Starter
Intermediate
Joined: Oct 2018
Posts: 39
Likes: 0
From: Jacksonville, FL
It used to be- 20 years ago- the constant power (yellow wire) was just to keep memory/clock- and pulled a small amount of power.
However -the yellow wire POWERS the radio totally these days- and can easily pull upwards to 10A.
The ignition source - red wire- JUST triggers the radio to come on- there is very little current draw (usually less then ½ amp)
So make sure you have a good clean source for power - or you are likely to get ignition/alternator noise.
Especially since new radios have USB inputs which are very susceptible to noise.
There's been several cases where going to the battery for both power and ground to the battery was required to get rid of the noise.
Richard
However -the yellow wire POWERS the radio totally these days- and can easily pull upwards to 10A.
The ignition source - red wire- JUST triggers the radio to come on- there is very little current draw (usually less then ½ amp)
So make sure you have a good clean source for power - or you are likely to get ignition/alternator noise.
Especially since new radios have USB inputs which are very susceptible to noise.
There's been several cases where going to the battery for both power and ground to the battery was required to get rid of the noise.
Richard
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