Adding AUX to 88-94 Stock Stereo

[Triplel40]

I'm looking to do this to my '89, however, I'd like to do things a bit differently so I've got a few questions I was hoping you guys could help with..

I don't like dip switches nor does the thought of running two cables (3.5mm & charge) get me excited.. Instead, I'd like to wire up the Aux switch to say a cargo lamp switch for a more factory look and then wire in a USB switch so I can run just one cable to my ipod. Has anyone done this? I assume I need a resistor to drop the voltage coming into the USB port to 5v? That aside, I figure I just need an accurate wiring diagram for the standard 30 pin Apple connector and just make the proper splices but I'd like confirmation to know if it is straightforward like that.

Looking at the diagram for a standard 30 pin Apple USB connector, it shows pins 1&2 on the USB connector lead to pins 25 & 27 on the 30 pin Apple connector which are labeled as "USB Data Negative" and "USB Data Positive" but would those actually send an audio signal or not when plugged into my Ipod? Seems all I have to do is splice pins 1&2 of the USB connector into the small black & red wire like depicted in the write up and then presto, I've got a USB input instead of a 3.5mm input. I'm hoping someone can confirm that because then I'll start ordering parts. I picked up an EQ tape deck radio at a boneyard this past Monday, I'll be testing it tonight and then if it checks out, I'll begin doing the mod..

Thanks for the help fellas!

Wow, really weird timing on your post seeing that I just started researching how to do this myself last night. Guess great minds think alike haha. In my brief research I found a few pin-outs for the 30-pin/lightning end of the connectors, but nothing so far that shows it at the USB end. I’m sure it’s out there just going to have to look closer, otherwise I’ll sacrifice an old charge cable and trace the wires. My plan is similar to yours except just tapping it into my existing setup. I figured run the charging circuit to a fused constant 12+ source and tap the analog audio parallel into my aux jack. Will research it more tonight. Let me know what you figure out and I’ll do the same.


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[DerekTheGreat]

Haha that's great.

I just typed something like "30 pin Apple USB connector wiring diagram" into Google and looked at the image results, sifted through them until I got a few which looked accurate. The one I looked at showed the pin traces so I cited them. I'm hoping they're accurate and that if I wire it up, they'll do as I intend them to do.

I think I'll do it much like you have it, as a 3.5mm jack would still be nice for non Apple stuff. It'll be a lot of splicing & such but if it works in the end, it'll be sweet and worth it. I'm so stoked about losing the garbage aftermarket Alpine junk thats all the way out in Sibera, AKA the middle of the dash.

ON a side note, I think you or someone else mentioned that the caps go bad in the unit which mounts under the dash. Since everything is sitting on the bench, I guess it would be worth it to take a look inside to inspect stuff. You wouldn't happen to know how to spot if stuff is bad or needs to be replaced, would you? I was originally just planning to test things by using my power supply thing to supply 14v to everything and then connecting one speaker to each of the four speaker outputs and listening for anything irregular.

 

[Triplel40]

Haha that's great.

I just typed something like "30 pin Apple USB connector wiring diagram" into Google and looked at the image results, sifted through them until I got a few which looked accurate. The one I looked at showed the pin traces so I cited them. I'm hoping they're accurate and that if I wire it up, they'll do as I intend them to do.

I think I'll do it much like you have it, as a 3.5mm jack would still be nice for non Apple stuff. It'll be a lot of splicing & such but if it works in the end, it'll be sweet and worth it. I'm so stoked about losing the garbage aftermarket Alpine junk thats all the way out in Sibera, AKA the middle of the dash.

ON a side note, I think you or someone else mentioned that the caps go bad in the unit which mounts under the dash. Since everything is sitting on the bench, I guess it would be worth it to take a look inside to inspect stuff. You wouldn't happen to know how to spot if stuff is bad or needs to be replaced, would you? I was originally just planning to test things by using my power supply thing to supply 14v to everything and then connecting one speaker to each of the four speaker outputs and listening for anything irregular.

Sounds good. I don’t know about components in the stock radios. I’ve heard the same about them having problems but mine is the original and still working. (Knock on wood).


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[DerekTheGreat]

Alright, tested the radio last night and everything works perfectly.

Now, can anyone point me in the right direction for a USB install kit? Seems everything I'm finding online connects to an existing USB port in your car, that it's purpose is to allow you to RELOCATE an existing port. That or simply charge using USB. I'm looking to charge and send the audio signal to the tape deck. Which USB port should I buy or did you buy and how did you wire it?

Here are some I'm looking at..
https://www.alliedelec.com/product/...VioTICh1fLgUAEAQYBCABEgKLafD_BwE&gclsrc=aw.ds

That is nice and slim, yet like mentioned above, it looks more like a relocation port.

https://www.gearbest.com/car-charge...MI0Z6Dz5CT4QIVioTICh1fLgUAEAQYFiABEgJb1fD_BwE

I like this one a lot too, as it allows me to also have a 3.5mm jack. How would I wire it though? Could I just lop the male USB end off and wire it straight to a fused 12v source while running the other leads to the tape deck as intended? My only hang up here is wiring the thing correctly, I don't want to fry my Ipod or anything else I try to plug into the USB socket.

Please help me!

 

[DerekTheGreat]

Well, in case anyone was looking for an update, here is the finished product! Looks 347% better than the aftermarket crap that was there and even sounds better, something I wasn't expecting.

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I ended up finding a different radio, one from an '89 which I never expected to find so everything matches. I didn't know this but in '88, the face and buttons were all black (Like the OP's), in '89 the face was silver/gray with black buttons as pictured and then '90-'94 were grey/grey. '94 saw a revision to the button grouping for the radio pod; the presets are grouped in a box rather than laid out left to right as pictured.

Here's what I used:
Switch:
Cargo light switch (any from '88-'94 will work, '88-'89 are black with gray rocker)

Aux & USB input:
https://www.ebay.com/itm/Car-Boat-Dash-Flush-Mount-3-5mm-AUX-USB-2-0-Extension-Lead-Panel-Cable-MA1128/192833341235?_trkparms=aid=111001&algo=REC.SEED&ao=1&asc=20180105095853&meid=979a3f7583fe46ecbbd1ea4a15764947&pid=100903&rk=2&rkt=3&sd=233198823554&itm=192833341235&_trksid=p2509164.c100903.m5276

Inverter/converter for USB:
Something from Powerwerx, but anything will do. I haven't wired mine up yet.

Speakers:
Two pairs of Infinity Kappa 64cfx's.
https://www.crutchfield.com/p_108K64CFXM/Infinity-Kappa-64cfx.html?tp=100

Some issues that perhaps you fellas can help with:
I'm getting ignition noise from the radio. So with the engine off everything sounds fine, auxiliary input or radio. With the engine running though, I'm getting engine/ignition noise regardless of the source. Any ideas what's going on? Now, I only mounted the radio amp section with two of the three fasteners, to do the other remaining one would mean ripping the ash tray out and slicing half my hand off to fit in there. Is that an issue? Is the auxiliary wiring it? I don't know much but I'd think it isn't as I'm getting the noise regardless of source.. Also, how far should the antenna cable seat into the socket? Mine didn't seem to sit very deep or tight as it should.. The previous radio (an Alpine from 2009) had no noise whatsoever.

 

[delta_p]

I did not see a schematic anywhere in this thread so it wasn't much use to me, but normally the noise issue is due to a ground.

Make sure the radio ground is attached. you can pull the antenna connection and see if the noise is still there to rule it out. I have a '96 that i did something similar but i broke into FM tuner feed to the radio internal amp to make the aux switch using the schematic below. I made sure the aux L,R,&G were as short as possible, i twisted them, and tied the ground directly to the chassis of the radio. There is no noise but with the switch in aux position there is just a hint of FM bleed over until my powered blue tooth input takes over.

The other possibility is it is on the speaker wiring, but doesn't sound like you changed anything there.

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[DerekTheGreat]

Thanks for the reply delta!

There was a schematic in the OP's original post, which is what I used to wire up my stereo and there was another one from a different post. With the items I used, you don't have to add a connector like the OP did as the things used already have them. I did anyway though because I like wasting time /s.

I forgot to mention that the combo aux input & USB connector had to be modified. I had to lop off the male end of the 3.5mm connector to splice into the factory harness. When I did that though, I was greeted with a Red, White, Green and Black wire. Nothing I found online described such a combination so I just assumed red was right and left was white as it typically is. No idea about the green and black so I just grounded both. But if that wiring was wrong, wouldn't it only want to make noise when using the aux input? And if the antenna connection was suspect, wouldn't the stereo only make noise when listening to the radio? The instructions provided by the OP did not say to ground directly the chassis of the stereo so I didn't, but I did wind the ground around the L&R wires of my aux splice job and then connected that to the ground lead in the stereo's harness.

Oh, yeah I did not make any changes to the speaker wiring, other than adding the adaptors and aftermarket speakers.

 

[Triplel40]

Thanks for the reply delta!

There was a schematic in the OP's original post, which is what I used to wire up my stereo and there was another one from a different post. With the items I used, you don't have to add a connector like the OP did as the things used already have them. I did anyway though because I like wasting time /s.

I forgot to mention that the combo aux input & USB connector had to be modified. I had to lop off the male end of the 3.5mm connector to splice into the factory harness. When I did that though, I was greeted with a Red, White, Green and Black wire. Nothing I found online described such a combination so I just assumed red was right and left was white as it typically is. No idea about the green and black so I just grounded both. But if that wiring was wrong, wouldn't it only want to make noise when using the aux input? And if the antenna connection was suspect, wouldn't the stereo only make noise when listening to the radio? The instructions provided by the OP did not say to ground directly the chassis of the stereo so I didn't, but I did wind the ground around the L&R wires of my aux splice job and then connected that to the ground lead in the stereo's harness.

Oh, yeah I did not make any changes to the speaker wiring, other than adding the adaptors and aftermarket speakers.

Hey sorry I haven’t been on here in a while, life has been busy. Glad to see you got the install done. I’m not sure about the alternator noise. I’ve never had any issues with it in my ‘88, but my uncles old 89 has it with the original untouched radio. I would suspect an issue in the stock radio is causing it, not anything you changed with the aux, since it happens listening to both sources. (They are 30 year old pieces of electronic equipment.) Might try tapping into the ground inside the radio and running a wire directly to a dash bracket, although I don’t know if it will work or not. (I’m not sure where the factory radio ground is. It goes up into the harness further than I have explored) Worst case you might be able to get an alternator noise filter and install it.

As for the wiring on your aux plug, there isn’t a set standard for colors. I have heard of RED and GREEN being left/right, but it’s anyone’s guess. An easy way to tell for sure, if you still have the male plug you cut off, would be to use an ohmmeter to test which wires are hooked to which ring on the plug, then consult a diagram of the rings for your style male plug.


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[DerekTheGreat]

Yep, that's what I did regarding the plug. So I was able to get the L&R channels sorted out but I didn't make heads or tails about the other two wires, so ground they were assigned. But I feel if I screwed that up, I'd have noise all the time and when the truck isn't running, it's perfect.

I will investigate further into the ground issue, probably all it is. Any idea how deep the antenna cable is supposed to sit into the radio? A pic would be handy too if you've got one.

 

[Triplel40]

Yep, that's what I did regarding the plug. So I was able to get the L&R channels sorted out but I didn't make heads or tails about the other two wires, so ground they were assigned. But I feel if I screwed that up, I'd have noise all the time and when the truck isn't running, it's perfect.

I will investigate further into the ground issue, probably all it is. Any idea how deep the antenna cable is supposed to sit into the radio? A pic would be handy too if you've got one.

I’ll post a picture of my antenna plug when I get home from work this afternoon.


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