Another stereo wiring question
09-27-2010, 08:14 PM
#1
Racer
Thread Starter
Another stereo wiring question
I'm replacing a head unit that I put in my car about 15 years ago. The car is an 86.5.
At the time, I didn't realize that the 12 volt power for the head unit was supplied through the stock amp that sits under the cover next to the front passenger seat.
Not knowing why I wasn't getting power to the head unit, I hooked it up by running a wire to the back of the car to the battery and had a lame toggle switch sticking out by the passenger side foot well to turn the stereo on and off.
I'd like to install this new head unit the right way.
Two questions -
1. Can anyone tell me specifically which wires that connected to the original factory amp should be bridged together to get power back to the correct 12 volt source for the head unit. I've taken a picture of the wires that are underneath the cover next to the passenger seat.
2. I've also taken a picture of the antenna wire. There is the main plug that connects to the head unit. There is also a smaller black wire bundled with the big antenna wire that has a small white plug on it. I never hooked this white plug up to anything. What is this small wire for? Would this explain why I've never had any AM radio reception with my current setup?
I know there are a bunch of threads about similar topics, but I've never seen the exact answer I've been looking for, so I figured it would be easier to post my specific questions with pictures.
Thanks.
At the time, I didn't realize that the 12 volt power for the head unit was supplied through the stock amp that sits under the cover next to the front passenger seat.
Not knowing why I wasn't getting power to the head unit, I hooked it up by running a wire to the back of the car to the battery and had a lame toggle switch sticking out by the passenger side foot well to turn the stereo on and off.
I'd like to install this new head unit the right way.
Two questions -
1. Can anyone tell me specifically which wires that connected to the original factory amp should be bridged together to get power back to the correct 12 volt source for the head unit. I've taken a picture of the wires that are underneath the cover next to the passenger seat.
2. I've also taken a picture of the antenna wire. There is the main plug that connects to the head unit. There is also a smaller black wire bundled with the big antenna wire that has a small white plug on it. I never hooked this white plug up to anything. What is this small wire for? Would this explain why I've never had any AM radio reception with my current setup?
I know there are a bunch of threads about similar topics, but I've never seen the exact answer I've been looking for, so I figured it would be easier to post my specific questions with pictures.
Thanks.
09-27-2010, 10:00 PM
#3
Racer
Thread Starter
If you're referring to the bullet connectors off to the right side in the second picture, that's another story...
Anyway, does anybody have an answer to one or both of my questions?
Thanks.
09-27-2010, 11:58 PM
#4
Three Wheelin'
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1. I'm pretty sure power for the radio does not go through the amplifier. It should be supplied through a chassis mounted choke on the red wire. Since you have a two-pin connector with red wires running off of them, I suspect that the choke is disconneted and should be hooked up to bridge them.
2. The wire that runs along with the antenna wire is for power to the signal amplifier. It should get 12V from the radio on the remote accessory line (the same 12V that turns on with the radio in order to turn on an amplifier). With it disconnected, the stock antenna will not have much FM reception.
2. The wire that runs along with the antenna wire is for power to the signal amplifier. It should get 12V from the radio on the remote accessory line (the same 12V that turns on with the radio in order to turn on an amplifier). With it disconnected, the stock antenna will not have much FM reception.
09-28-2010, 06:20 AM
#6
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Without the WSM wiring diagrams in front of you it's tricky to work out. And there was something wierd about the factory wiring in that it used an ignition switched +12v from the amp to turn on the head unit.
Simplest way is to use a meter to work out which wires at the amp location have ign switched +12v and which has permanent +12v. Do the same in the stereo harness in the central console. If it's red and never gets power at the central console or at the amp location, disconnect the battery then check for connectivity between amp and centre console.
However if you have a thick wire with ign switched +12v and a thin wire with permanent +12v at the centre console already forget the amp location.
Simplest way is to use a meter to work out which wires at the amp location have ign switched +12v and which has permanent +12v. Do the same in the stereo harness in the central console. If it's red and never gets power at the central console or at the amp location, disconnect the battery then check for connectivity between amp and centre console.
However if you have a thick wire with ign switched +12v and a thin wire with permanent +12v at the centre console already forget the amp location.
09-28-2010, 07:11 AM
#7
Craic Head
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Hey Tom,
Here's what I did:
1. Remove the entire harness and bundle of wires underneath that amp cover.
2. Tap into the power from the cigarette lighter and interior lights input from the clock (power is on with acc, lights will switch/dim with the interior lights)
3. Have a beer.
Here's what I did:
1. Remove the entire harness and bundle of wires underneath that amp cover.
2. Tap into the power from the cigarette lighter and interior lights input from the clock (power is on with acc, lights will switch/dim with the interior lights)
3. Have a beer.
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09-28-2010, 09:16 AM
#8
Rennlist Member
The 86 wiring diagram shows it all pretty well. You need it.
The antenna amp is located at the base of windshield, behind dash, passenger lower corner.
It is hooked to the windshield filament, assuming you still have an "antenna windshield".
I've got a spare amp from JHowell and can show a picture if necessary.
The little wire accompanying the antenna signal wire is indeed for power. I hooked one up last week to a little wire on the radio bundle (check its diagram) that feeds power from the radio when radio is on. WSM shows that little wire also branching and connecting to the amp white wire. Not sure why it needs to go to the amp. Mine is a car with amp removed, and a new sony radio, so just the radio wire hookup worked.
Alternately, you can run separate 12 V power to the antenna wire, so long as it switches off/on with key in accessory position.
The WSM diagram shows suppressers on 12V feed lines to prevent static. (There is also grounding of coils that helps with interference and should be a ground wire from the wiper motor to the body for same reason. This information is from a tech service bulletin in early 85 or 86 that talks about how to retrofit a windshield antenna to a pre-85 car and the necessary mods to get good reception.)
The antenna amp box I think is also grounded to the body with the mounting bolt, up under the dash, where it mounts and that is important. One more ground connection to chase! Don't go there if it seems to work, but if it doesn't give good reception, do.
Like Mike says, you can hook directly to 12v power. Radio has a wire that gets full-time power, and another that gets part time power (key in accessory).
The antenna amp is located at the base of windshield, behind dash, passenger lower corner.
It is hooked to the windshield filament, assuming you still have an "antenna windshield".
I've got a spare amp from JHowell and can show a picture if necessary.
The little wire accompanying the antenna signal wire is indeed for power. I hooked one up last week to a little wire on the radio bundle (check its diagram) that feeds power from the radio when radio is on. WSM shows that little wire also branching and connecting to the amp white wire. Not sure why it needs to go to the amp. Mine is a car with amp removed, and a new sony radio, so just the radio wire hookup worked.
Alternately, you can run separate 12 V power to the antenna wire, so long as it switches off/on with key in accessory position.
The WSM diagram shows suppressers on 12V feed lines to prevent static. (There is also grounding of coils that helps with interference and should be a ground wire from the wiper motor to the body for same reason. This information is from a tech service bulletin in early 85 or 86 that talks about how to retrofit a windshield antenna to a pre-85 car and the necessary mods to get good reception.)
The antenna amp box I think is also grounded to the body with the mounting bolt, up under the dash, where it mounts and that is important. One more ground connection to chase! Don't go there if it seems to work, but if it doesn't give good reception, do.
Like Mike says, you can hook directly to 12v power. Radio has a wire that gets full-time power, and another that gets part time power (key in accessory).
09-28-2010, 09:44 AM
#9
Race Car
Hey Tom,
Here's what I did:
1. Remove the entire harness and bundle of wires underneath that amp cover.
2. Tap into the power from the cigarette lighter and interior lights input from the clock (power is on with acc, lights will switch/dim with the interior lights)
3. Have a beer.
Here's what I did:
1. Remove the entire harness and bundle of wires underneath that amp cover.
2. Tap into the power from the cigarette lighter and interior lights input from the clock (power is on with acc, lights will switch/dim with the interior lights)
3. Have a beer.
09-28-2010, 10:42 AM
#10
Racer
Thread Starter
Hey guys,
Thanks for all of the replies. They should help a lot. I tend to make tasks way more complicated than they need to be, so this should only take me a few hours to sort out. Then I can do step 3 & 4.
I just printed out the wiring diagram. Wish I had paid more attention in high school electronics class...
The unplugged antenna booster would explain my nonexistent AM reception and my FM reception was never really great. The car still has its original antenna windshield.
Thanks again.
Thanks for all of the replies. They should help a lot. I tend to make tasks way more complicated than they need to be, so this should only take me a few hours to sort out. Then I can do step 3 & 4.
I just printed out the wiring diagram. Wish I had paid more attention in high school electronics class...
The unplugged antenna booster would explain my nonexistent AM reception and my FM reception was never really great. The car still has its original antenna windshield.
Thanks again.
09-28-2010, 11:10 AM
#11
Three Wheelin'
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Without the WSM wiring diagrams in front of you it's tricky to work out. And there was something wierd about the factory wiring in that it used an ignition switched +12v from the amp to turn on the head unit.
Simplest way is to use a meter to work out which wires at the amp location have ign switched +12v and which has permanent +12v. Do the same in the stereo harness in the central console. If it's red and never gets power at the central console or at the amp location, disconnect the battery then check for connectivity between amp and centre console.
However if you have a thick wire with ign switched +12v and a thin wire with permanent +12v at the centre console already forget the amp location.
Simplest way is to use a meter to work out which wires at the amp location have ign switched +12v and which has permanent +12v. Do the same in the stereo harness in the central console. If it's red and never gets power at the central console or at the amp location, disconnect the battery then check for connectivity between amp and centre console.
However if you have a thick wire with ign switched +12v and a thin wire with permanent +12v at the centre console already forget the amp location.
I am not seeing what you're talking about as far as switched power coming FROM the amp (see U/R of page 5). I am seeing switched power coming through the choke to pin 2 on the radio (2.5mm Red). The White wire that powers the antenna amplifier also turns on the amp.
09-28-2010, 03:26 PM
#12
Electron Wrangler
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None of those connectors shown above is stock - most of those wires are for speakers. The switched power to the radio/head comes from the ignition swithch via a supression inductor/choke located under the radio on the (LHD) drivers side of the console - looks like a transformer. Big Red wire.
The smaller red wire from the Amp supression inductor/choke located under the sill cover (where the amp is) feeds the continuous supply to the head unit in thois model year. This wire may be too small for many modern head units w/ buolt in amps.
The antenna extra wire is for the Antenna amp - you will get crappy or no reception unless you power this when the head unit is on - most head units have an antenna on or amp on trigger signals - if they have adequate drive you can use either of these - if you have both use antenna for the antenna and amp for the amp (of course).
Alan
09-28-2010, 07:31 PM
#13
Racer
Thread Starter
Thanks again for the replies.
I figured out which is the 12V switched wire and will also use the permanent 12V wire from the clock. Should be good to go with that.
For the antenna - If I understand correctly, I should run power from the head unit (tapping the remote turn on lead?) to the little black wire for the antenna booster. Does that sound right?
Note: In the top photo of the two in this thread, all of the wiring seen is as it was when I removed the original factory amp....aside from the duct tape course. The original stereo was in the car and functioning when I purchased it.
I figured out which is the 12V switched wire and will also use the permanent 12V wire from the clock. Should be good to go with that.
For the antenna - If I understand correctly, I should run power from the head unit (tapping the remote turn on lead?) to the little black wire for the antenna booster. Does that sound right?
Note: In the top photo of the two in this thread, all of the wiring seen is as it was when I removed the original factory amp....aside from the duct tape course. The original stereo was in the car and functioning when I purchased it.
09-28-2010, 08:25 PM
#14
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I believe the antenna gets power from the 'antenna' wire (is it blue) from the head unit.
The speaker wires (+) are your standard Clarion/Jenson color code (Purple, green, white, gray) with the Brown being grounds
Big brown is amp Ground
Pick up the power from under the console (black box)
U can use the ashtray light for your dimmer (brown i think) wire that dims the radio when the lights come on.
The speaker wires (+) are your standard Clarion/Jenson color code (Purple, green, white, gray) with the Brown being grounds
Big brown is amp Ground
Pick up the power from under the console (black box)
U can use the ashtray light for your dimmer (brown i think) wire that dims the radio when the lights come on.
09-29-2010, 10:25 AM
#15
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This is backwards - the head unit turns on the amp.
None of those connectors shown above is stock - most of those wires are for speakers. The switched power to the radio/head comes from the ignition swithch via a supression inductor/choke located under the radio on the (LHD) drivers side of the console - looks like a transformer. Big Red wire.
The smaller red wire from the Amp supression inductor/choke located under the sill cover (where the amp is) feeds the continuous supply to the head unit in thois model year. This wire may be too small for many modern head units w/ buolt in amps.
The antenna extra wire is for the Antenna amp - you will get crappy or no reception unless you power this when the head unit is on - most head units have an antenna on or amp on trigger signals - if they have adequate drive you can use either of these - if you have both use antenna for the antenna and amp for the amp (of course).
Alan
None of those connectors shown above is stock - most of those wires are for speakers. The switched power to the radio/head comes from the ignition swithch via a supression inductor/choke located under the radio on the (LHD) drivers side of the console - looks like a transformer. Big Red wire.
The smaller red wire from the Amp supression inductor/choke located under the sill cover (where the amp is) feeds the continuous supply to the head unit in thois model year. This wire may be too small for many modern head units w/ buolt in amps.
The antenna extra wire is for the Antenna amp - you will get crappy or no reception unless you power this when the head unit is on - most head units have an antenna on or amp on trigger signals - if they have adequate drive you can use either of these - if you have both use antenna for the antenna and amp for the amp (of course).
Alan
Shouldn't post late at night. I was probably remembering the continuous power feeding from the amp to the head unit.
WRT head units and amplified in screen antennas - these have a markedly different impedance to a typical stick antenna. It is well worth finding the antenna tuning pot on the head unit (normally a small hole in the case somewhere) then tune to a weak am station and tweak the antenna pot for maximum signal strength (best signal).
