After adding some accessory power wiring (12VDC) to my truck, I began noticing an issue with the onboard compass going wacky when the accessory was powered (less than 1/4A current draw). I suspect I may have routed the new wiring near whatever sensor (hall-effect??) is used to determine the compass direction. Before I tear the dash or cab apart again, can anyone tell me where this sensor is located in a 2016 SCrew? Any relevant info appreciated.

 

The GPSM (Global Positioning System Module) is located in the center area of the dash. There is a self-test you can run if you have a diagnostic tool or FORScan (not a generic reader) which will generate DTCs if there are problems.


If it needs replacing, the PMI (Programmable Module Installation) process must be performed.

 

The GPS provides the information for the compass display. In my low end 2015 non navigation, the GPS antenna is in the middle of the dash, its under the middle top portion that you remove to access the Sync3 display. If you have Navigation, I believe its on the roof.

 

With or without Navigation, the GPSM is the same.

 

It's either inside the GPS antenna, or GPSM is being used to determine heading, as unplugging that antenna also kills the compass.

 

It uses the GPS Module? I figured it was independent of everything else and used some kind of flux-gate sensor like nearly every other electronic compass I've had. I figured I had passed my DC power wiring too close to this sensor. Well. I guess that would explain a few things. Symptoms that I never connected before. The accessory that seemingly makes the compass go wacky will also occasionally confuse my iPhone's navigation capabilities. This notably sucks when I'm using the phone for navigation via CarPlay.

What is it, you ask? A 5.8GHz video RECEIVER. When towing my camper, I have a wireless link to a camera on the rear of my travel trailer. This arrangement has, on more than one occasion, saved my rig from harm (It's shaped like a brick. It's not meant to go fast. Go around!). Anyway, more than once I have watched my compass totally flake out, sometimes displaying the exact opposite of the actual direction of travel. When the iPhone's GPS malfunctions, it tends to place the icon representing my vehicle in fields adjacent to my actual highway location, drifting randomly. What this tells me is that both the truck's GPS and the iPhone's GPS radios are being affected.

I looked it up. GPS signals operate in the GPS L1 Band (1575.42MHz), GPS L2 Band (1227.6MHz) and the GPS L5 Band (1176.45MHz), all of which are significantly below the incoming signal from the video transmitter 35+ feet away inside my trailer. Well, since I've never used the receiver without the transmitter, I think the next step is to try them independently to see which one is actually causing the interference. If it's the transmitter, then it looks like I'm SOL. Without it I can't see behind the trailer. If it's some signal leaving the receiver's plastic case, then maybe a bit of creative shielding will protect the GPS signals at the truck. In any event, the whole transmitter/receiver/camera set-up only cost me about $20 plus the time to wire it. Maybe someday I'll graduate to a real RV camera system....

Thank you all for your input here. Its great feedback from people like you that encourages participation in these forums.

 

Everything is handled by a module these days. My surprise was the steering column control module, a computer to control the blinkers.

Also, where did you buy this device? I'm surprised it's affecting the navigation systems because the FCC forbids this type of thing for safety reason. I wonder what the range is and if it's able to affect vehicles and devices surrounding it?

 

Sorry for the long delay in replying. Just haven't bee online much lately. The 5.8GHz transmitter/receiver pair in question was purchased off of Amazon this past spring, but surely made somewhere in southeast Asia. Similar units can be found on ebay too with a variety of fake brand names. Yeah, I'm pretty sure I've narrowed it down to the receiver. I'll probably end up waiting until next spring to deal with the issue though.

packrat