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Factory wiring help (reverse & park signal)

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Hi, I've had a good search but can't find the answers so thought i'd ask the hive mind.

We have a (new to us) Alphard AH10, 2007 3.0. I have replaced the factory stereo with a Kenwood DMX5020DABS - all good except for two things that I need help with.

1 - The reverse camera works, but doesn't trigger automatically when going into reverse. Can someone tell me what wire/pin to connect the trigger wire on the Kenwood unit to in the car loom please?

2 - I can't setup the reverse camera lines as the head unit needs to be told it is in park. I can get around this by temporarily grounding the wire to do the setup, but if there is a park signal wire in the loom I can just connect to that, so same question to the forum please - is a park signal cable in a loom behind the factory stereo, and if so, can someone point it out to me?


Thanks in advance, I had hoped to be able to download or find the wiring line or pin-out diagrams online but they are either unverifiable and behind a paywall, or don't seem to exist.

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  • 2 weeks later...

When you sorted out the reverse camera, did you have a separate lead to tell the head unit that the car is in reverse? I've just put in a new head unit but the connection is a phono video in, not the standard four pin plug. I have ordered an adaptor that splits the cable to a phono plug and a power and earth, but I need to be able to tell the unit when I engage reverse.

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Hi, yes I did - in hindsight I should have taken a picture. There is a 3-pin connector into the original unit that has a feed that is live when reverse is active. I’m pretty sure one of the others is a light signal for auto-dimming the unit but I didn’t connect that or test it. 

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I have an Android unit that has the lead marked for the reverse which is the signal in cable. Then I have another attachment with a female phono connector and has two short wires coming out of it. I picked up an adaptor from ebay for the Alphard which has a male phono connector and positive / negative connectors on, with a resister to lower the voltage. It's just trying now to find the feed to tell the unit that I am reversing.


The car had an aftermarket stereo in that was badly wired up. It had the option for the reverse camera but did not work, so I have no idea if the cable is actually still there or been cut off. 


I found a video online that looks like one of the plugs, but it has four wires. I'm hoping that is the one, but have to pull the new unit out to try it.



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That is what I did - I also bought the camera adaptor. The plug you showed was the right one on my car too, and the woring colours were correct. It works on mine with the factory camera perfectly once I found the reverse signal wire in the loom. 


I grounded the parking brake wire on the Kenwood head unit also as it wouldn't let me setup the parking grid lines due to it thinking it was in gear all the time. 

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  • 2 weeks later...

A had a question this morning and the answer seemed like it might be useful to some others at some stage, so i'll post it here. This is a list of what I bought to fit the stereo in, reatining the factory rear camera (including settting up the reverse grid on the Kenwood) and the steering wheel controls. Most was ordered from InCarTech in Exeter.


 1 x Toyota Alphard/ RAV4 Audio Steering control interface with camera retention - (29-648-RAV4CAM)   £65.83 (each)
 1 x Kenwood steering wheel control input patch lead for 29-XXX series steering control interfaces - (29-005)    £3.33 (each)
 1 x Toyota double DIN radio fascia adapter panel, side fixing brackets - (50-282)   £12.49 (each)
 1 x Dashboard trim panel tool (4 Pack Assorted) - (85-207)    £8.33 (each)
 1 x DAB  11db internal windscreen active antenna - (70-924)   £29.16 (each)
 1 x USB extension to dashboard socket - (24-017)   £12.49 (each)


I have had trouble with the DAB antenna, so would advise not to buy that one. A cheap splitter/adaptor from Amazon for the origional radio antenna works much better and saves a load of money. 




I should say all the above is for an AH10 with a Kenwood 5020DABS head unit replacing the factory small head unit without the amplified stereo. I had an issue with the camera wires on the InCarTech loom and had to splice some of those manually - not sure if this was an issue with my car or not, but just something to be aware of. I also had to find the reverse signal wire in the existing loom manually, and had to ground the handbrake wire from the Kenwood headunit in order to setup the reverse parking lines.


We also upgraded the factory sepakers to a set of BLAM from InCarTech (front & rear) and this has made a massive difference to the sound. There are a few thigngs to look out for if upgrading the front speakers so let me know if this is on your to-do list also.

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