I purchased a 2018 Ford PIU after my 2015 PIU got totaled. The 2015 I was able to use a Metra system and install an aftermarket radio with little to no problems what so ever. I think the biggest head scratcher was where to run the amp wiring through. After purchasing the 2018 3.5L with the rear AC, I was ecstatic and ready to go. Well, Its now November and I still cant find a work around to get the aftermarket stereo to work.
Ive attempted to install the Metra system, which fit perfectly but WOULD NOT OPERATE THE AC. It would throw the rear ac on and full Heat. Purchased three different HVAC modules for it, and still the same results. My next step was to try installing a different radio bezel, ended up finding a wrecked 2013 Explorer that had the 8inch but it used the old style plug. I depinned the plug for the radio bezel and then used a wire plug that matches it to attempt to get it to function through the stock system. I was able to get the hazards to function, but the other buttons wouldnt work. I am unaware if this was due to water damage in the accident or wiring issue.
After throwing in the towel on that, I pressed into the Idatalink realm. The radio I originally purchased is a Pioneer CH5500 Nex, which can use the Idatalink system, which includes displaying the temperature of the HVAC. The problem spawns from here, when I installed the original metra wiring harness, I was able to get power to the radio without a problem, just the HVAC didnt want to work with it.
Well, the Maestro RR MFT-1 wiring harness doesnt carry power directly to the radio like most harnesses. It feeds a 12v constant to the Maestro RR module and then directs voltage out to the head unit. Im pretty confident that this may work as a work around, but my PIU is a 4.2 inch model without sync. I contacted Idatalink support about why I wasnt getting power to that portion of the harness but the 12v constant was running fine and I was told by the support branch flat out that the Maestro RR does not work with the 4.2 inch system.
Im pretty much tapped right now, although Im confident that the Maestro system would work if you could figure out the wiring.
If there are questions in regards to this and thats to what I used, message me and Ill inform you.