First Gen Premium Sound System -- 85 B2

[BlackBII]

I don't know what the inside of your radio looks like, but basically what you need to do is override the preamp signal with your bluetooth receiver, so that your radios amp plays the music/calls.

This is how I did it, but my radio is of the newer digital style. Not sure what yours will have

There is also this company, who may make one that works for your dash

https://www.retromanufacturing.com/

Finally got around to adding an aux input to my factory radio. I tried the Bluetooth board I bought, but kept having ground noise issues, so I just used an aux cable instead.

I soldered the left and right wires of the aux cable to the L and R #2 inputs(AM Radio) on the preamp chip and ground to ground. This way I still get to use the chips equalizer and balance settings. I desoldered the AM tuner connections so that I won't get any buzzing. So now if I want AUX, I set the radio to AM. FM Radio still works great.

Here's some pics and the data sheet of the chip in my radio. Note - The left and right are shown here as being soldered to the #3 inputs. I switched these later to the #2 inputs, overriding the AM signal.
My phone puts out too much voltage, so I'll have to add a 100k trimmer pot so I can tone it down, but my battery powered 3.5mm Bluetooth receiver works great.

1992 factory radio with added Bluetooth round 2.

I added a step down voltage converter and an isolated 12-5v converter.

This got rid of the ground loop noise.

 

[ford4wd08]

I don't know what the inside of your radio looks like, but basically what you need to do is override the preamp signal with your bluetooth receiver, so that your radios amp plays the music/calls.

This is how I did it, but my radio is of the newer digital style. Not sure what yours will have

There is also this company, who may make one that works for your dash

https://www.retromanufacturing.com/

Thanks for the info.

I might just go the aux input route and have something else stand alone for bluetooth.... Just have to see.

 

[ford4wd08]

This is an interesting option for not much money.... I've used Isimple products before. They seemed to work well....

https://www.amazon.com/iSimple-IS31-Antenna-Modulator-Aftermarket/dp/B002U5XPBE

 

[ford4wd08]

Also this option..... Hmmm.... might be easier than I thought....

https://www.amazon.com/iSimple-Hands-Free-Calling-Streaming-Smartphones/dp/B00FRU5UNA/ref=sr_1_3?dchild=1&keywords=isimple&qid=1591202749&s=electronics&sr=1-3&th=1

 

[BlackBII]

Yeah those will work!. They are effectively doing the same thing, only they're passing the signal through the radio receiver. I wanted to avoid doing that to prevent any interference, and I also wanted to have all the components hard wired internally.

 

[ford4wd08]

I can see where that would be of benefit.

I am guessing that with this being in the antenna spot, surely it would be better than the ones that just plug into the cigarette lighter.

Also, this supposedly blocks the signal from the antenna.... I'll probably gamble on this as an easy install.