Hi all, to get the rear screen working while the car is moving I need to fool the unit into thinking the park brake is on all the time. Can anyone shed any light on to which wire is it coming out of the factory radio which is a Panasonic CQ-HS01JOBJ. There are a lot of wires back there to choose from and none of them are pink like the wire that comes off the actual parking brake.

RESOLVED - READ ON!

OK so I have found out a few things.

I decided to muck around with the park brake wire down at the pedal. I ended up moving the micro switch style things slightly on the bracket so that the button didn't get pressed when the park brake was released, so the radio (and the car) always thought the handbrake was still on... Great until you hit 5kph and the warning chime starts chiming.... Aarggghhh. Back to the drawing board and that's where this post came in... Where is the wire on the radio that tells the system the park brake is on or off, I'll ground it so only the DVD will think the hand brake is still on and not the rest of the car system.

Tried for ages in vein to find a wire that would give me some joy but came up empty handed.

Chatgpt suggested that this unit gets it's information about park brake status from Canbus information and not a physical wire. So it would be pretty hard for me to cheat the system. I thought it was over and admitted defeat.

Maybe a new head unit sometime down the road, one that had a physical park brake wire that could easily be fooled or one that would just play the video out to an external monitor without the need to be tricked into it.

Little side note the wiring at the back of the Panasonic unit was not what I was expecting, instead of a dedicated "video out" it has a piggy back plug going into one of the smaller plugs and out of that has some rcas heading into a splitter black box with rca from the Alpine rear screen.

So here I am thinking I'm done, then I thought of something I hadn't tried after extensive talks with Chatgpt about what's going on.

It hit me that there was something I hadn't tried... I had moved the microswitch down at the pedal but I hadn't actually disconnected it from earth - it earths when it is bolted to the pedal hoising, I had just moved it slightly previously so this time I unscrewed it and tucked it away, so no chance it can connect to earth, this created more of an "error state" park brake neither on or off and the next thing blew me away...!

So now the head unit screen just shows blue, no changing with the foot brake on or off or standing still or moving, and I thought that obviously the rear screen would show whatever the front screen was showing, as before...

So I opened the screen and blow me down it's playing the damn video and audio is working fine (it always kept working previously). So off I went for a drive and yep still working! AND no pesky buzzer or dash light either. WINNING!

Some of you might have cottoned on to the one and only problem here, I can't see the front screen at all no matter what so can't access DVD menus, the DVD does auto play so it's not all bad but going forward I will reinstate the micro switch at the pedal but I will cut the wire and join it with a simple toggle switch running up to somewhere within reach, so that when parked I can toggle it back to standard setup and can see the front screen as normal.

What really gets my goat is that it obviously could be done (playing rear screen while vehicle moving while isolating front) but they went the most "compliant" route.

Multiple hours of mucking around when all it actually needed was 5 minutes to remove the black plastic shield above pedals and removing feet vent piping to get to the screw that holds the park brake micro switch. Boom.

There are two wires.

A parking brake, and a speed sense wire.

Please add a photo of the back of the unit and I'll post the correct wires

Hi there!

In theory, the correct operation would be to keep the rear screen playing while in motion, but turn off the front, a safety setting!

The reverse of how yours has been set up.

But - you say the head unit is Panasonic and the rear screen Alpine - so it would be probable one has has been changed at some point in it's life?

Doesn't help solve it, but could explain why the problem exists 😯

Cheers, Nev

Here's a photo of the back.

1 hour ago, BigNev said:

Hi there!

In theory, the correct operation would be to keep the rear screen playing while in motion, but turn off the front, a safety setting!

The reverse of how yours has been set up.

But - you say the head unit is Panasonic and the rear screen Alpine - so it would be probable one has has been changed at some point in it's life?

Doesn't help solve it, but could explain why the problem exists 😯

Cheers, Nev

Yes that's how I would have thought it would be like, that the rear screen would continue to play while only the front screen turned off while in motion, makes sense to me but because the rear turned off as well it was very frustrating for that to be the case, and I thought it was because of the way it was wired - no front output = no back output but that obviously is not the case as I have just proved.

2 hours ago, BigNev said:

Hi there!

In theory, the correct operation would be to keep the rear screen playing while in motion, but turn off the front, a safety setting!

The reverse of how yours has been set up.

But - you say the head unit is Panasonic and the rear screen Alpine - so it would be probable one has has been changed at some point in it's life?

Doesn't help solve it, but could explain why the problem exists 😯

Cheers, Nev

The front screen is branded toyota in the outside but it is Panasonic when you take it out so it's definitely the factory radio. The Alpine could be a factory or dealer option, the vehicle is a Jap import into New Zealand. The wiring inside tells me it's not factory but the unit "looks" factory as in its a great install, there is also an av input at the base of the centre console which doesn't work but I haven't actually checked if it's hooked to anything.