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Adaptive Cruise Control fault after manipulating fuse box


New member
I installed a piggyback fusetap for my radar detector (because it's hard not to speed in this thing). I plugged into F47 (rear windshield wiper).
After doing this and running the hardwire up the A pillar and attaching the radar detector to the underside of the rearview mirror, suddenly the ACC doesn't work. The yellow fault light for the cruise control is on on the dash and also alerts at everty startup, and I cannot activate the ACC.
Why would this installation have caused this? I took out the piggyback fuse and put things back where they originally were and it didn't fix the problem.
Any ideas?


New member
I had this happen too when I was doing hardwire for my radar, as mentioned before check all your fuses. In my case it was 7.5 amp fuse but I had faults with electronic parking break.

I also took a picture of all the fuses so i knew how to put them back properly :)

The Fed

Old Guys Rule
Test the fuse. Did you tap in on the hot side or cold side? And are you going to use the detector and the rear defrost at the same time? Does your radar detector have its own fuse?