I have replaced the stereo in my 89 LX with an aftermarket Bluetooth stereo. I bought the wiring adapter to plug into the factory harness. The unit powers up fine but no sound from the speakers. I tried another stereo, same thing. That's when I noticed the factory harness only has 5 speaker wires where there aftermarket plug has eight wires. Am I correct in assuming that there are 4 positive wires and 1 common ground in the factory harness? If so can I just repin the aftermarket unit to run all the positives to the positive connection on the factory harness and then wire the 4 ground wires to the common ground of the factory harness?
Fox stereo speaker wiring
- Thread starter modeladdict
- Start date
No. That is incorrect. The 5-wire plug is your radio power/ground and illumination wires
The speakers are an 8-wire plug. Since you don't see this plug, i assume you have the premium sound radio in which the 8-wire speaker plus is connected to the amp harness.
The standard and premium sound radio are all wired like a 4-channel radio. Premium sound has speakers, but the door and dash are considered a channel and wired in parallel through the OEM amp harness. But each channel gets a 12V+ and ground.
Which OEM radio are you starting with? Is this a premium sound car with 6 oem speakers, or 4? If premium, did you pull the OEM amp and wiring out? Photos would help here
Here’s the base radio wiring diagram. There are two additional wiring diagrams depending on if you have premum sound, or the premium sound with EQ radio. BUT, when you install an aftermarket radio, you remove the amp and harness and are just left with the two body plugs simlar to the base radio. One with 5 wires and one with 8.
Wire colors should be listed below
Please not. The door speakers are wired through the amp harness in the OEM setup. When you remove the amp harness or bypass it, you are no longer powering the door speakers so you need to physically wire them into the dash speakers in parallel
Wire colors should be listed below
Please not. The door speakers are wired through the amp harness in the OEM setup. When you remove the amp harness or bypass it, you are no longer powering the door speakers so you need to physically wire them into the dash speakers in parallel
Yeah, you have the premium setup. You are plugging into the factory amplifier harness.
The plugs in your hand are the plugs circled in red. What you need to do is reach up behind the radio and locate the plugs circled in blue. Plugged into those will be two plugs that look very similar to the ones circled in red. Plug those into your aftermarket radio harness. Verify it works.
The two unmarked plugs go to the amplifier unit itself. You can actually remove the factory amplifier and this harness and put it on ebay if you want. Your headunit probably outputs a higher wattage than this amp so you don't want to run your aftermarket radio through it. It's likely why you didn't have sound.
PLEASE NOTE: the 87-89 cars feed the dash speakers through the amplifier harness. The above harness is a 90+, but on the 87-89 cars you will have two small plugs branch off and plug in at the doors. Those are the door speakers. When you bypass this amp harness and remove it, you lose the door speakers. You will need to take the two plugs at the doors and wire them into the dash speakers in parallel.
The plugs in your hand are the plugs circled in red. What you need to do is reach up behind the radio and locate the plugs circled in blue. Plugged into those will be two plugs that look very similar to the ones circled in red. Plug those into your aftermarket radio harness. Verify it works.
The two unmarked plugs go to the amplifier unit itself. You can actually remove the factory amplifier and this harness and put it on ebay if you want. Your headunit probably outputs a higher wattage than this amp so you don't want to run your aftermarket radio through it. It's likely why you didn't have sound.
PLEASE NOTE: the 87-89 cars feed the dash speakers through the amplifier harness. The above harness is a 90+, but on the 87-89 cars you will have two small plugs branch off and plug in at the doors. Those are the door speakers. When you bypass this amp harness and remove it, you lose the door speakers. You will need to take the two plugs at the doors and wire them into the dash speakers in parallel.
If your car has a factory amp for the stereo it is in fact behind the factory radio and is held down with two fasteners. Looks like a football and sounds worse. In 1993 they moved it to under the passenger seat which is where mine was on my '93.
With regards to wiring the door speakers and the dash speakers in parallel I would caution people to use a 100 MFD capacitor on the positive lead close to the 3-1/2" speaker in the dash which will knock the base out of them. To be more technical the capacitor in this case is a passive crossover that limits the lower frequencies to that speaker.
From what I remember the facotry door speakers pretty much naturally roll off at the frequency the capacitors are blocking on the dash speakers. So when you utilize the capacitors and wire these speakers up in parallel you are not creating a larger load on the head unit. I will try and clarify this a little bit. For example, when wiring two 4 ohm speakers in parallel you drop the impedance that the amp or head unit sees down to 2 ohm which they may not be stable at. Remember that wiring speakers of the same impedance in parallel you divide the impedance by the number of speaker coils so in the case of my example 4/2 = 2. However since the door speakers roll off at the frequency that the capacitor is blocking on the dash speakers load wise it looks like one speaker to the amp or head unit so it is basically a 4 ohm load.
Maybe you wanted to know all of this and maybe not.
With regards to wiring the door speakers and the dash speakers in parallel I would caution people to use a 100 MFD capacitor on the positive lead close to the 3-1/2" speaker in the dash which will knock the base out of them. To be more technical the capacitor in this case is a passive crossover that limits the lower frequencies to that speaker.
From what I remember the facotry door speakers pretty much naturally roll off at the frequency the capacitors are blocking on the dash speakers. So when you utilize the capacitors and wire these speakers up in parallel you are not creating a larger load on the head unit. I will try and clarify this a little bit. For example, when wiring two 4 ohm speakers in parallel you drop the impedance that the amp or head unit sees down to 2 ohm which they may not be stable at. Remember that wiring speakers of the same impedance in parallel you divide the impedance by the number of speaker coils so in the case of my example 4/2 = 2. However since the door speakers roll off at the frequency that the capacitor is blocking on the dash speakers load wise it looks like one speaker to the amp or head unit so it is basically a 4 ohm load.
Maybe you wanted to know all of this and maybe not.
TIGGER
Founding Member
Scrapla347
Active Member
I'm replacing my factory speakers and gonna add the 100 MFD capacitor to my tweeter. Thanks for the info before I destroyed my new head unit.
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