I installed a Directed DB3 module with T-harness. Directed is what most "pre" built kits use...IE: 12v solutions and various others...etc.
It's very easy to do remote start on our cars. I tapped 3 wires from the DB3 module into the T harness and then it plugs directly into the BMC. Zero soldering/cutting of the stock wiring. Took MAYBE an hour.. I got my Lexus T-harness from
Home - T- Harness Guy (tharnessguy.com) Note I am NOT affliated at all with this site/person. But I did communicate with him on FB and he made the T-harness for me for the BCM.
Best of all it's cheap if you DIY.
Directed DB3 module: $70.
T-Harness: $30
Total Cost= $100. You save $100+ or more depending on which kit you'd buy from some place else...etc.
Don't let the bundle of wires throw you off. The top harness is what plugs into the OBDII port, that then goes into the DB3 module.
The second set of wires below that, only 3 are used. See second picture for what it goes to. (NOT) pictured in my first pictures is the T-harness I bought so that I
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3 wires to tap into the BCM harness. If you use the T-harness you connect the wires into that. Then it's just plug and play. If not you COULD use t-taps and do the BCM harness but I prefer to not tap into oem wiring if I don't have to.
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*T-Harness so that way you don't have to cut/solder ANY wires onto the OEM harness. A plug and play, completely reversible mod when it comes time to sell.
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That's it.
Super easy mod to do! Uses the OEM keyfobs and just like OEM. Three presses of the lock button will start the car.
-Nigel