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So I have an 86 v6 firebird and am looking to upgrade to a Bluetooth head unit. The car currently has a really old pionner unit. I read on one of the posts here that aftermarket units can cause the system to not work? It already has an aftermarket unit so I was confused by what the poster ment.
"the 86 Firebird is the UQ7 sound system. This was the premium sound system in the Firebird (85'-89'). It does have a small amp under the dash near where the map pocket is. The amp powers the small 5 inch subs in the rear sail panels. There are 4 x 6 inch speakers are above them, and two 4 x 6 inch speakers in the front of the dash, so its a 6 speaker system. The system is designed to work with any of the GM factory stereo radios of the era: the UM6, UM7, UX1, and the top of the line UT4. It *will not* work with aftermarket stereos."
I am a little confused on what will stop working with an aftermarket unit. Does anyone have a bit of clarification? also is there anything i should be aware of when instaling or removing the units? All tips appreciated very much.
I don't "know", but I would "guess" he means that the factory radio provide a pre-amp output to the UQ7 amplifier. If an aftermarket head unit only had line level outputs (amplified outputs), this would not work (you can send an amplified signal into an amplifier).
My 1987 wiring should be the same as your 1986. The picture below shows how to make the factory amp work with a 4thgen radio using a 3rdgen to 4thgen adapter harness, and it does work. The blue wire on the car's side has to be spliced/tapped to a power wire. Might work the same way with an aftermarket radio harness. The aftermarket radio's harness might even have a dedicated output wire for a sub, so if no aftermarket sub is being used, then splicing the blue wire to that wire might do it, otherwise, splice/tap it to the red wire, similarly to what I've done. What's the worst that can happen?
My 1987 wiring should be the same as your 1986. The picture below shows how to make the factory amp work with a 4thgen radio using a 3rdgen to 4thgen adapter harness, and it does work. The blue wire on the car's side has to be spliced/tapped to a power wire. Might work the same way with an aftermarket radio harness. The aftermarket radio's harness might even have a dedicated output wire for a sub, so if no aftermarket sub is being used, then splicing the blue wire to that wire might do it, otherwise, splice/tap it to the red wire, similarly to what I've done. What's the worst that can happen?
Not trying to hijack but I’m trying to piece this system back together in my 86 to test for a video. I’m using a 4th gen radio like you. Do you know if the 4 main speakers also run through the UQ7 amp? The system was in pieces when I got the car. I managed to get the sub boxes for cheap and re-foamed the woofers. The gain switch lights up when pressed, but dims and the subs move without any audio output. I’m assuming the amp probably needs a re-cap, but I also want to make sure the head unit is compatible. Is your system still working well with that 4th gen head unit?
Not trying to hijack but I’m trying to piece this system back together in my 86 to test for a video. I’m using a 4th gen radio like you. Do you know if the 4 main speakers also run through the UQ7 amp? The system was in pieces when I got the car. I managed to get the sub boxes for cheap and re-foamed the woofers. The gain switch lights up when pressed, but dims and the subs move without any audio output. I’m assuming the amp probably needs a re-cap, but I also want to make sure the head unit is compatible. Is your system still working well with that 4th gen head unit?
Yes, everything worked with my 4thgen radio, including the subs. But I've since wired up a 2DIN android radio that does more than my cell phone, and the subs work with it too. I see in your driving video that your 4thgen radio is a Monsoon version, which has more features than the same non-Monsoon 4thgen radio like mine. Looks good in the car, better than 3rdgen radios. Interior looks good too. Those 4thgen Firebird seats are nice.
I wouldn't have thought all of the speakers would run through the amp, but I've never had my amp out to look at its wiring, and the connector is on top of the amp, where you can't see it without dropping it down. But looking at the service manual, it appears that all of the speaker wires do run to the amp. The picture of the amp's connector has 15-pins, and an online picture of an amp shows a 15-pin receptacle, which would account for 4 speakers, 2 subs, power and the gain switch wires. Your speakers sound good, so your amp is apparently working or, at least, not interfering.
The pink wire in the car's connector is for the amp and the power antenna. In the adapter harness I pictured, that's the blue wire that I've cut. But I don't have a power antenna, and it looks like a post for a fixed antenna on your car too, from what I can see when you're not waving the cam around lol, so cutting that blue wire is ok, since there's no antenna to power up. The place I got the adapter said to power that blue wire with the red wire, so I did, but I'm not sure it was necessary to cut it after all. Because if that blue wire is carrying power to the antenna, then it should also be carrying power to the amp, unless power antennas only require a pulse and not full-time power, so maybe 4thgen and aftermarket radios only send a pulse, but that's just a guess. But if you haven't cut that blue wire yet, then I'd test it uncut and untapped first to see if the amp is getting power.
Edit: Sorry, I see you said the amp is getting power. Not sure what you mean by no audio output, but the subs send the deep bass, a beat, like a bass drum, and the gain slider intensifies it. If you're not hearing anything at all, then maybe the slider just needs to be exercised a bit, or maybe the switch isn't 100%.
Last edited by LAFireboyd; Mar 7, 2026 at 02:04 AM.
Yes, everything worked with my 4thgen radio, including the subs. But I've since wired up a 2DIN android radio that does more than my cell phone, and the subs work with it too. I see in your driving video that your 4thgen radio is a Monsoon version, which has more features than the same non-Monsoon 4thgen radio like mine. Looks good in the car, better than 3rdgen radios. Interior looks good too. Those 4thgen Firebird seats are nice.
I wouldn't have thought all of the speakers would run through the amp, but I've never had my amp out to look at its wiring, and the connector is on top of the amp, where you can't see it without dropping it down. But looking at the service manual, it appears that all of the speaker wires do run to the amp. The picture of the amp's connector has 15-pins, and an online picture of an amp shows a 15-pin receptacle, which would account for 4 speakers, 2 subs, power and the gain switch wires. Your speakers sound good, so your amp is apparently working or, at least, not interfering.
The pink wire in the car's connector is for the amp and the power antenna. In the adapter harness I pictured, that's the blue wire that I've cut. But I don't have a power antenna, and it looks like a post for a fixed antenna on your car too, from what I can see when you're not waving the cam around lol, so cutting that blue wire is ok, since there's no antenna to power up. The place I got the adapter said to power that blue wire with the red wire, so I did, but I'm not sure it was necessary to cut it after all. Because if that blue wire is carrying power to the antenna, then it should also be carrying power to the amp, unless power antennas only require a pulse and not full-time power, so maybe 4thgen and aftermarket radios only send a pulse, but that's just a guess. But if you haven't cut that blue wire yet, then I'd test it uncut and untapped first to see if the amp is getting power.
Edit: Sorry, I see you said the amp is getting power. Not sure what you mean by no audio output, but the subs send the deep bass, a beat, like a bass drum, and the gain slider intensifies it. If you're not hearing anything at all, then maybe the slider just needs to be exercised a bit, or maybe the switch isn't 100%.
I did some digging and found out the 4 speaker channels do pass through the amp, but just to supply a signal for the rear subs. Unfortunately the amp doesn’t do anything to boost the 4 channel audio, it just powers the subs. I pulled the amp apart today and found a leaking capacitor. The issue I’m having is the gain switch lights up when pressed, but then dims and the subs start oscillating in and out without the gain or radio volume even turned up. Apparently this can be a sign of bad capacitors.
I’m in the middle of replacing them all now so we’ll see what happens. And thanks, yeah the 4th gen eq radio fits the car nice and they’re waaaay cheaper than the 3rd gen variants. I actually just swapped the Monsoon cd player out for a cassette deck version from a grand am. I feel like cassette player just fits the car better, plus I have cassettes I can play.
My end goal is to test out the stock system complete with the subs working, then swap out the stock subs for something better to maybe use as midbass drivers. I can tie them into a 4 channel amp with the front and rears, then use a coil inductor to keep them below 500hz or so. I also want to add a small 8 inch sub in the spare tire area and tie it into the gain **** so it actually functions. I think this will make a really balanced system as the regular 6x9’s in the sail panels always seem to struggle with any kind of midbass in my experience. Plus the gain **** turning on the separate sub amp and actually adjusting the gain would be amazing. We’ll see how it goes..
I did some digging and found out the 4 speaker channels do pass through the amp, but just to supply a signal for the rear subs. Unfortunately the amp doesn’t do anything to boost the 4 channel audio, it just powers the subs. I pulled the amp apart today and found a leaking capacitor. The issue I’m having is the gain switch lights up when pressed, but then dims and the subs start oscillating in and out without the gain or radio volume even turned up. Apparently this can be a sign of bad capacitors.
I’m in the middle of replacing them all now so we’ll see what happens. And thanks, yeah the 4th gen eq radio fits the car nice and they’re waaaay cheaper than the 3rd gen variants. I actually just swapped the Monsoon cd player out for a cassette deck version from a grand am. I feel like cassette player just fits the car better, plus I have cassettes I can play.
My end goal is to test out the stock system complete with the subs working, then swap out the stock subs for something better to maybe use as midbass drivers. I can tie them into a 4 channel amp with the front and rears, then use a coil inductor to keep them below 500hz or so. I also want to add a small 8 inch sub in the spare tire area and tie it into the gain **** so it actually functions. I think this will make a really balanced system as the regular 6x9’s in the sail panels always seem to struggle with any kind of midbass in my experience. Plus the gain **** turning on the separate sub amp and actually adjusting the gain would be amazing. We’ll see how it goes..
I’d consider a Sony XM-GS6DSP amplifier for the expanded system.
5/6 channel (front left, right + rear left, right & sub), more than enough output to give impactful sound (actually have some bass).
high level inputs (run the factory speaker cabling right into amp with no adapter), amp will generate a subwoofer output from these inputs.
Bluetooth playback (bypass that gimpy Bluetooth dongle in your 4th gen deck) and have some real adjustments from your phone.
Amp has an on board Digital Signal Processor for use with Bluetooth playback. Dial in that listening seat with an iPhone GUI.
You’ll be able to bi-pass the speakers in the sail panel to whatever frequency you choose, high pass the fronts & low pass the sub in the spare tire well, easy peasy setup.
The amp has a remote level input (think gain slider 👍 that can be used as a subwoofer gain ****.
that can be used as a subwoofer gain ****.