Where can the rear defroster wire be connected at?

Question

2010 Subaru Forester. I want to connect the rear defogger/defrost to the remote start. Where is the wire and how do I tap into it?

Wirecolor said it was the harness was at the BIU, a blue wire, but wirecolor has been wrong before. I've tried testing this wire with a multimeter, but am getting odd results. If I can tap this wire at the harness, do I program for pulse or latch? Do I need a relay? The wire form the remote start is 200mA(-).

Answer 1

Use multi meter to confirm said wire is ground. Use multimeter in Amp mode (make sure leads are in Amp mode) and ground one lead, putting other lead on wire. Should trigger rear defrost. Note current. If it triggers and current below specs then just tap wire, no need for relay. Use latch till shut down and I use activate below 41 degrees option so its auto.

Comments

It should be only be measured as grounded with defrost activate. You might get some resistance on the meter and that might be what your seeing. Its not a straight short. But if your meter activates defrost in Amp mode within specs then your good. It will be trigger to factory relay.

---

I was measuring it with positive lead to 12v+ and the negitive lead at the wire.

---

The wire doesn't activate in Amp mode. Either wirecolor is wrong, or I have completly missed the wire location. Where I am look is a black box with two harness connecting to it far under the dash. Box is vertical. I need the location of the wire, I can't seem to find it.

 

Another question; when testing the wire and trying to trigger it, does the harness need to be plugged in? I tried it both ways with this wire, but if I have to test everone to find the right one, it would be much eaiser unplugged.

---

Harness needs plugged in and cars ingnition on.