Rear Dash Cam Cable Interferes with Key Antenna on Driver's Side

[KFT2]

In case this may be helpful for anyone, if installing a dash cam with a rear camera the cable should be run along the passenger side of the headliner.

I had a dual camera dash cam and the video cable for the rear camera was run along the driver's side of the headliner. I started noticing that I would get a message asking if the key was still in the car if I would open a window. sunroof after the car was running or intermittently need to hold the key fob up to the start button to start the car. I always suspected the rear camera video cable must be interfering with the key antenna in the car. It was generally such a minor thing that I just lived with it. Until recently I upgraded the dash cam and took out the rear camera cable, confirmed car no longer loses the key signal if I open a window. Installed new setup with the rear camera cable instead routed on the passenger side of the headliner and no issues with it there.

[Audisthesia]

Mine runs drivers side, zero issue. I'd say its more to do with quality of the cable and it's proper shielding (or not) than location as there are KESSY sensors on both sides of the car.

[Avantly]

What are you powering the dash cam with? Based on past experience I estimate that upwards of 90% of cheap 12V->5V buck regulators used in cigarette lighter USB chargers, 12V->5V power supplies for dash cams, etc which are made in china and "self certified" for EMI (assume that nearly every single dash cam 5V power supply fits this description) would actually pass no EMI test at any lab anywhere. I have seen some Amazon cigarette lighter phone chargers with emissions so bad that they knock out the AM and FM radio in the car, or render the capacitive touchscreen on the phone or car's navigation system partially inoperative. Using a shielded wire unlikely to help as these emissions will ride on the surface of the shield, radiating in every which direction (it's called the skin effect). So what you were observing was due to the magnitude of the noise being emitted by the power supply, that was riding down the surface of that cable and radiating away from it. The measured power of this radiation is squared if you halve the distance to the wire, i.e. being very close to it will result in measured noise being many magnitudes higher than if you were measuring only a foot or two away from the wire. I'll bet if you switched out the power supply with a name brand 5V adapter, the problem would go away.

[KFT2]

Good point on the power adapter possibly being the delta. The actual rear camera cables between the old and new dash cam look to be very similar. Old dash cam was run off of a "Spytec" dash cam hardwire kit hooked up to the fuse panel on the left side of the dash. New dash cam is a plug and play kit that has a Y cable to the rain sensor for power.

[Avantly]

Good point on the power adapter possibly being the delta. The actual rear camera cables between the old and new dash cam look to be very similar. Old dash cam was run off of a "Spytec" dash cam hardwire kit hooked up to the fuse panel on the left side of the dash. New dash cam is a plug and play kit that has a Y cable to the rain sensor for power.

Interesting. So it is tapping into 12V at the rain sensor and then bucking it down to 5V there. It could likely be the quality of that buck converter. Or it could be something as simple as grounding strategy - The rain sensor is low power and maybe that ground wire travels all the way down to the pillar before it is grounded. Grounding strategy can have a massive effect on radiated/conducted emissions. I wouldn't doubt that if a noisy buck is the issue, it could cause enough noise in that rain sensor circuit that it also no longer works as intended xD

[Siouxpercharged]

I would use caution if routing the dash cam wires along the headliner due to the side curtain airbags. Make sure they're behind the airbags so in the event the airbags deploy, there's no interference. I routed my rear camera wire down, along and under the sill panels, and back up the a-pillar and over to the camera.

[Burkeomatic]

Aren't those in the A Pillars? They're quite simple to route above/behind the airbags though. I don't run a rear dash cam, maybe I should. If I do, i'll just do a separate one instead of wiring it to the front one, so you get HD front and rear.