Mrmerlin

I have to install a pioneer MVH P7300 AV receiver player in a 928 .
The issue is, one of the wires has to go to the Hot side of the E brake so to allow the unit to play video when the E brake is set,
they dont want to allow video play with the car in motion.

Now since the E brake circuit is set with a ground whats the best place to connect said wire to the Hot side of the circuit, ground wire goes into the dead pedal warning computer at pin 5. any ideas??

John Speake

So does the radio unit need a 12v signal to allow it to play video, or a ground ?

WallyP

Easy way would be to pop a Scotchlok on the brown/yellow wire anywhere in the run. Other choices are to connect at the switch, or at Black 5.

Scotchlok is easy and can be removed. Not totally reliable (but this is not a critical application) and it cuts the wire insulation (but if you install in a dry area, the cuts are usually insignificant). I hate them in most applications, but might be tempted this time...

Mrmerlin

John in the install directions it wants a 12 volt positive connection,
as opposed to a 12 v ground connection the wire already has a scotchlock connector on its end it just need to be tapped onto the correct 12V positive wire.

Wally in the directions it specifically shows a switch with a 12V hot to switch then a 12v to ground and the wire gets connected to the 12 V hot side.
and in the notes it says not to connect the ground side of the switch.

I have not tried to connect to a ground or hot yet but the only positive i can see is at the instrument cluster warning light

Mrmerlin

Here is the note from the install manual

To ensure safe driving
WARNING
! LIGHT GREEN LEAD AT POWER CONNECTOR
IS DESIGNED TO DETECT
PARKED STATUS AND MUST BE CONNECTED
TO THE POWER SUPPLY SIDE
OF THE PARKING BRAKE SWITCH. IMPROPER
CONNECTION OR USE OF
THIS LEAD MAY VIOLATE APPLICABLE
LAW AND MAY RESULT IN SERIOUS INJURY
OR DAMAGE.
! To avoid the risk of damage and injury and the
potential violation of applicable laws, this unit
is not for use with video that is visible to the
driver.
! To avoid the risk of accident and the potential
violation of applicable laws, no viewing of
front seat video should ever occur while the
vehicle is being driven.
! In some countries or states the viewing of
images on a display inside a vehicle even by
persons other than the driver may be illegal.
Where such regulations apply, they must be
obeyed.
When you attempt to watch a video image
while driving, the warning Viewing of front
seat video source while driving is strictly
prohibited. will appear on the front display.
To watch a video image on the front display,
park your vehicle in a safe place and apply the
parking brake.
4


Parking brake interlock
Certain functions (video viewing and certain
operations) offered by this unit could be dangerous
and/or unlawful if used while driving.
To prevent such functions from being used
while the vehicle is in motion, there is an interlock
system that senses when the parking
brake is set. If you attempt to use the functions
described above while driving, they will become
disabled until you stop the vehicle in a
safe place, and (1) apply the parking brake, (2)
release the parking brake, and then (3) apply
the parking brake again. Please keep the
brake pedal pushed down before releasing the
parking brake.
Operation

borland

The Pioneer installation manual shows the handbrake wire connected to the handbrake switch wire, switch leading to ground....

http://www.pioneerelectronics.com/St...nual011111.pdf

On my 90' the parking brake switch wire goes directy to the instrument cluster, so you can't pick up that signal wire from the CE panel.

John Speake

Ok Stan that seems clear :- +12v inhibits video, ground activates video. Most switches in the car are switching hot to ground, which saves on wiring.

Mrmerlin

Thanks Borland, for posting the manual, on the second page, I think you should look at the diagram again,
it clearly shows the green lead connected to the power side of the switch and the 928 doesnt have +12v at the switch.

So John are you saying that it will function correctly if I tap into the ground switch wire?

Or If i just ground this wire will it always be able to run the video?
I was trying to make the system work as advertised,
IE no video with the hand brake off

John Speake

Stan, I think you will find that there is 12v to the handbrake switch (handbrake off). The circuit clearly shows the switch grounding that wire to activate the warning lamp.

Have you measured at the switch ?

Yes, grounding the wire would allow video with handbrake on or off.

WallyP

Stan,

I think that my suggestion is correct. The brown/yellow wire from Black 5 to the switch should be hot when the ignition switch is on, and grounded thru the switch when the parking brake is applied.

John Speake

x2

Mrmerlin

Off to measure the grounding wire .

OK with the ground wire connected to the volt meter I get 12V then with the handle pulled its grounded thanks for all the info fellas.

Answer connect the green wire to the brown E brake ground wire.

borland

Stan,

The Pioneer unit's hand brake wire is not drawing any power from the car, so I does need 12V power. It is a signal wire, not a power wire. Your voltmeter may see 12V, but you can't draw any significant power from it, only a few miliamps at most.

As a signal wire, it is looking for is the same thing that the instrument cluster is looking for at the handbrake switch; and that is a ground signal which is only present when the hand brake is set.

Mrmerlin

Borland thanks again could you please proof read your post I dont understand it .

To be clear the green wire is a signal and only needs a signal , in other words its looking to be grounded to allow the video function to work?

WallyP

No, it sounds as if it is looking for a 12 volt signal to disable the video. When the 12 volt signal goes away (brake up) the video is enabled. You need to hook to the brown/yellow feed wire to the switch, not the brown ground wire from the switch to ground.