Sync 3 Navigation issue

Hi guys,

I am having a very interesting issue with my Sync 3 nav unit. This is a Sync 3 unit that was swapped in for my MTF system since my car is a 2015.

So, when my car is parked in the garage and I leave for work, the arrow is in the correct location on the map and facing is east as is my car. I back out of my driveway and get on to the road, the nav is working fine. Once I start driving forward, the arrow still points towards north, but it starts going in the OPPOSITE direction of my actual travel. And it mirrors my actual actions (if I take a right to go east, the arrow turns east but heads west, but it is not even on the same road as I am). The nav does the exact opposite of what my car is doing. Now, if I reset the Sync unit while driving by pressing down the power and right skip button together for 5 seconds and let the unit reboot, the nav then works properly.

I noticed that the nav starts doing this backwards business whenever my car is parked in a location with a roof over the vehicle, affecting the GPS signal. I just don't understand why doesn't the unit reset its location when it has a good clear view of the sky. I mounted the GPS antenna in the same area where the GPSM is usually located in these cars. Anyone have any idea what the hell is happening because I cannot find any useful information anywhere?

Thank you.

Alright, so this is more bizarre than I thought. It is not when the car is under a roof. It messes up when I REVERSE! So if I back out of my garage the GPS messes up. For some reason it the GPS keeps thinking that I am backing up when I actually start going forward. :shrug: Anyone have any idea what is going on because I am just amazed at this point.

Where did you get the upgrade? Have you reached out to them for help?

I have the same problem. Tried two different brands of GPS antennas and still the same thing.

I even tried different mounting location and still nothing.

I had the same issues with my conversion and i also have a cheap ebay gps antenna. I did all the same things as you. What i found to have worked was doing a master reset and then Just leaving it alone. It took about four days before it stopped acting up. I think it goes through a learning phase but it works perfectly fine now with no hiccups

I have the same issue in a factory sync3 system. Has anyone found a solution yet?

i have the same problems. I purchased 2 Sync3 units from the wreckers for myself and my wife's car. They both work in the 15 Edge and they both get lost in the 15 Mustang. also noticed the when using Waze in carplay it gets off track just the same.
Tried all the suggested fixes, mount new GPS antenna where orig was on a thin steel plate,
needed to change APIM in Forscan to manual transmission, and some other changes but with no luck yet.
this has been discussed alot in thread "SYNC 3 swap, It's all in here"

I did the swap last year and have the same problem, anybody found a solution? Works fine as long as I don't reverse.

From my kit. Not sure if this will help.

Optional Programming:
If you have an issue with low volume make this change in the ACM if not already made.
ACM 727-01-01 xx0x xxxx xx
Factory NAV owners - if the compass is backwards check this in the APIM.
Manual Transmission: 7D0-01-02 xx9x xxxx xxxx
Automatic Transmission: 7D0-01-02 xx0x xxxx xxxx

racingandfishing said:

From my kit. Not sure if this will help.

Optional Programming:
If you have an issue with low volume make this change in the ACM if not already made.
ACM 727-01-01 xx0x xxxx xx
Factory NAV owners - if the compass is backwards check this in the APIM.
Manual Transmission: 7D0-01-02 xx9x xxxx xxxx
Automatic Transmission: 7D0-01-02 xx0x xxxx xxxx

Click to expand...

It worked! My car is a manual but the apim was set to the automatic code and when I changed it to xx9x the problem is gone. Thanks for the solution.