01-25-2026, 10:06 PM
Hi! I'm going to retrofit the alarm and motion sensor to my 2018 XC40.
I thought it had an alarm because the red light was flashing, but no… there's neither an alarm nor a sensor. The sensor mounted in the dome light has factory wiring, so it's just a matter of installing it, but the alarm under the windshield wipers has no wiring at all, and I'll have to make some myself.
I know it has three wires:
-red (fuse 30)
-brown (negative)
-purple???
Can anyone tell me where to connect the brown and purple wires?
I thought it had an alarm because the red light was flashing, but no… there's neither an alarm nor a sensor. The sensor mounted in the dome light has factory wiring, so it's just a matter of installing it, but the alarm under the windshield wipers has no wiring at all, and I'll have to make some myself.
I know it has three wires:
-red (fuse 30)
-brown (negative)
-purple???
Can anyone tell me where to connect the brown and purple wires?