Pacer Performance 20-702 Black Logic Circuit

This product has a bunch of bad reviews from folks who have likely tried to use it on vehicles with LED combined brake/signal lights. It does say in the description that it doesn't work with LEDs, but it can, if you're comfortable adding two resistors. I'm an electrical engineer, and have verified this worked on my module. The module won't care if the third brake light you're connecting is LED or not. But if your existing combined turn+brake lights are LED, it won't work right, because it doesn't see a strong enough path to ground when the lights are off. As a result, the third brake light will flash when either turn signal is activated. What you need to add are called "pull-down resistors." You'll need one on each turn signal wire. In my test, 1kOhm wasn't enough, but 680 Ohms worked great. You'll want to buy 1/2 Watt resistors, so that they can easily handle the heat. See my drawing for installation details. This is an unpaid review, no warranty or guarantees from me implied or otherwise. :-)

Used on the advice of eTrailer to send a combined brake light signal to my trailer brake controller because a brake light signal was not available under the dash. Worked around the block, but sometime during our trip I discovered that it had died and was sending blinking signals to my brake controller instead. Replaced with "Truck cap third brake light Logic box # AT-LC-4:" from American Technology Components and the replacement has worked perfectly.

Followed directions and worked perfectly.

This is the lazy man's way of wiring a break light for your truck cap. I had my Leer cap installed on my 2014 F-150 by a Leer dealer and they did the wiring which included installing this device. Had i known that is what they were going to do, i would have stopped them and done the correct wiring myself using the factory provided wire for this purpose. However, the device was already installed so fast forward 6 years and my cap brake light is not working. I checked and instead of 12v going to the light i was only reading 1.3v on the meter. I popped out my tail light and found the plastic outer casing was cracked and broken on the device. I ordered a replacement from Amazon and wired it in. Installation only took 10 minutes since all I had to do was cut the wires to the old device and solder/shrinkwrap them to the new device. I am taking off 1 star because the build quality is pretty low. Something like this device should really last much longer than 6 years if it was built with higher quality materials.

This unit is very misleading. It claims to cancel unwanted turn signal in the third brake light but only does so when brakes applied. Any other time it still flashes the third brake light. So if you are using your turn signal (Left or right) without any brake pressure applied it still flashes with the turn signal. If you are using your turn signal and applying brake pressure. It will cancel the signal. Would I recommend it, no. Should I send it back yes but it's not worth me paying return shipping on a $10 part. So I'm just going to eat itand use it for what it is. Beware.

If your pick-up cap or topper was not dealer installed this item is a 'must have' if you want the CHMSL to work correctly. That is, if your brake/stop light and signal lights are a double filament bulb, otherwise the CHMSL will blink when using your signal. That is not only annoying but illegal in most states. This unit solves the problem and makes for a professional looking installation. The need for an additional wire run from the brake light switch back to the CHMSL is eliminated. You only have to run a wire from the right brake light to the left making installation much easier. Once installed, the logic circuit basically 'lies' to the CHMSL whenever you use your signals allowing the light to stay lit when brake is applied and signal in use. Highly recommended and a must have if you want things done right.

Worked great - but you must connect to both directionals so that the 3rd light does not blink with directionals. Mine does blink when the hazards are on - I do not see that as a problem. I did not need resistors like others have suggested - it may be that the leds that I have on a trailer have a built in resistor.

Product is supposed to take individual brake light wires from L & R side and use logic to apply 3rd brake light. My truck has standard incandescent (non LED) tail lights. I wired it up and the 3rd brake light flashed whenever either the left or right signal was on. I am an electrician and understand how to wire things. Does not work - even on incandescent tail lights. Returned.