Dave_R

Problem 3. Microphone inputs no longer working. Problem 4. Radio doesn't work well - sounds like antenna is perhaps not connected properly. Problem 5. USB connector cable fell down the back of the dash and I can't reach it These are all problems to be worked on next weekend! Progress reports to follow. For now everything important works, CarPlay audio, navigation, steering wheel controls are all ok. My car does not have roof video or 18-speaker sound so I can't speak to those functions. I left the original physical aircon controls in place so no issues there.

Problem 2. Reversing Camera The reversing camera did not work out of the box. The MOST box/wiring harness I bought included a small controller labelled CANBUS but which is actually a GVIF to RCA video adapter. I was confused for a while because the car does not have a blue reversing cam video connector. It does have a green GVIF connector but thats for in-car video entertainment (I think - please correct me if anyone knows). Again I eventually tried using a small android to RCA video cable (pictured) that came with the head unit and connected the RCA end to one of the two yellow RCA sockets on the MOST harness. This proved to be the correct thing to do but I did not know because there head unit was supplied with 360° camera software, but the car does not have 30 cams, just a regular reversing camera . I will not say how many hours I spent trying to configure the 360° cam software to use the reversing cam, but after much trail end even more error I git into the Facoty Settings and disabled the 360° camera software and, like magic - but with more colourful language - the reversing camera started working as expected. The car's steering-responsive curved reversing guides don't show up any more but I can live with that. Mostly. The GVIF-RCA converter was not needed in the end.

Problem 1. Audio Plugging everything together went well. The 16-pin Android head unit, the MOST box, and the car plugs all go together and there's generally only one way as the connectors are all unique to each other. The head unit turned on successfully and its now time to test all the functions. Bluetooth and CarPlay worked. I was able to pair my phone and control the head unit. Because it's Android based you have to manually run the "TLink" app to enable Carplay. Now the first issue became apparent - no audio. I was unable to get any audio from the speakers at all. At last, in desperation I connected the head unit's AUX audio out to the MOST box AUX audio in and suddenly we are wired for sound. To do this I had to use the RCA connector harness that came with the head unit. This has an android 20-pin connector on one end and a whole bunch of RCA connectors and a GPS on the other end. The MOST box came with an RCA AUX input cable already attached. Its partly visible at the bottom of the photo below but it's just two RCA plugs for Left and Right audio. With these AUX connectors connected audio works and it sounds pretty good. Note: there's a lot of misinformation in the labelling of these audio harnesses. They talk about fibre optics but there are no optical fibres in 2nd generation Alphards/Vellfires. I believe its a digital audio connection between the head unit and the under-seat amplifier and thats what the most box provides - it converts analog audio from the new head unit to digital format for the amp. This is all done on copper wiring so not really fibre optics at all. Some people avoid all this by removing or bypassing the amplifier and installing a new analog wiring loom from the android head unit to the amplifier speaker outputs, but thats seems like a lot of work. There are YouTube videos showing how to do it if you are interested. Installing the MOST box avoids all that extra labour and uses the existing wiring. As a bonus the MOST box includes CANBUS so I found that steering wheel controls for example worked as soon as I'd told the head unit that the car was an Alphard.

I read all the advice in these forums and searched through the Ali Express listings for Alphard/Vellfire Android wiring harnesses. After a few false starts I found this one which appeared to have all the right connectors. "16PIN Android Radio Power Cord Wiring Harness For Toyota Alphard Vellfire AH20 2008-2015 Car stereo Fiber Box Adapter Canbus" https://www.aliexpress.com/item/1005006000618979.html

After removing the head unit the connectors look like this. Note that not all connectors on the head unit are connected.

The original head unit looks like this. Back panel and identifying part number 26041 on the front. My car is a 2009 Vellfire GGH20W Japanese import. It has the high spec head unit with GPS navigation and hidden Minidisc player, but does not have 18 Speaker sound system. It does have an amplifier under the front passenger seat but I can only see 9 speakers - maybe there are two more somewhere.

Hi, I have managed to replace this head head unit with a generic android head unit. It wasn't entirely straightforward so here are the details in case they're helpful for anyone else.