Uniden Smart Cord Schematic


PSL +5
Intermediate User
Jan 14, 2019
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Like the install... Wondering what happens when you hit the trunk release as you're going for the Mute button... Speed brake?
luckily the trunk button needs to be held for 3 seconds to pop the trunk


Learning to Drive
General User
Apr 22, 2019
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Good stuff. This should be useful for integrating my R3 with my gauges.


Learning to Drive
General User
Jul 15, 2014
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so, guys, I hate to bring up an old thread, but this seems to have the most technical knowledge.

I bought and eBay mirror tap and it's been working great for a year. unfortunately I was trying to get it to work with my new valentine1g2. it wouldn't work. I remember, they would always be interchangeable.

so, I plugged my R7 into my valentine1 cig adapter and it works, just to test the interchangeability. anyhow, afterwards, I plugged the R7 back into my mirrortap, GUESS what? it doesn't work. I thought I fried a fuse, but no, it still works with the cigarette adapters.

next, I take apart the ebay mirrortap. the guy has it wired to pins 1 and 3, ie, the "alert" wire and the 12v+ wire. that explains why it doesn't work with the V1. BUT, why did it work with the R7 and why doesn't it work anymore. did I cause some damage?

ebay mirrortap not wired properly, but worked for 1 year. now it doesn't work after I tried plugging it into v1 cigarette adapter.


I basically took apart my smart cord and started reverse engineering it...

View attachment 79453

The red box is a +12V supply filter consisting of a 100uF Electrolytic cap and a smaller ceramic cap to filter ripple voltages(not sure the size without removing it from the board, likely 1-10uF).

The blue box consists of basically a +5V power supply and some resistors for the USB charger. The chip, U1, is an HC8813 DC-DC step-down(buck) voltage regulator. R8-R11 are resistors that tell your device, such as a phone, to start charging when it's plugged in.

The rest is what most of you are going to be concerned about. K1 is the momentary push button used to mute the detector. It has a capacitor, C5(1nF), to dampen it. The LED is fed by +12V and has a 6.8K ohm resistor. There's also an NPN transistor that is used by the detector to enable the LED when it's powered on and also flash the LED when there's an alert. I used a BC547 in my schematic below because its a TO-92 package and easy to solder or breadboard.

Below is a quick schematic of how the push button and LED are wired.
A = Alert which is the white wire in the Uniden cable
S = Switch which is the green wire
GND is black
+12V is Red
View attachment 79454

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