Stereo Upgrade

[Ranger Pete]

Is the parking brake circuit ground or +12 volts. Going to bypass it with a switch for video playback.

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[airline tech]

Hmm - The Park Brake (Applied) switch is a single wire feed from the BCM (Power) and the switch itself provides the ground (when applied)

However this is BCM (output) controlled and it may not be a 12 volt power feed, may just be 5 volts. You would have to pull the connector and check for power with key on - if you require a 12 volt signal to get (watch video ) signal to the head unit.

Note - if your intentions are to bypass the circuit (remove the switch) from the circuit and bypass the signal straight to ground (watch while driving) keep in mind that the BCM is monitoring the circuit and will trigger warnings when you place the gear in drive - same as having a door opened. (This is Can Bus) monitored in addition to the park brake light being (illuminated)

 

[Ranger Pete]

I'm not removing the switch from the parking brake. Simply connecting the parking brake wire from the head unit and connecting it an on/off switch to either ground or +12 volts, which ever the head unit needs to see.

 

[airline tech]

Understood - but if the new head unit must see - 12 Volts to Ground (Circuit)
or just any completed circuit - is the question?

Point is you will need to try it or check the parking brake switch connector (key on) and see if it is 12 volts or 5 volts, its depending on what the head unit wants (specific 12 volts?)

We know that the voltage is provided by the BCM, open circuit = Light Off, pull the handle circuit is complete = Light On - So if the head unit (Req's a 12 volt input) then this signal (MAY NOT) work and it depends on if the BCM is providing 12 Volt Power on this circuit - (It may not be) and may only be pushing 5-Volts.

Basically tapping the circuit should simply work, but if you have issues - it may be due to the voltage output from the BCM and the answer to your question is - BCM Power looking for a ground to complete the circuit (switch closed) - so now it falls to what specific input does the after market head unit want or need for the input logic that the park brake is applied - a simple closed circuit or a voltage specific circuit - which the BCM may limit that requirement - so if you have issues of it not working (this will be the source of it)

Not trying to over complicate it - just pointing out a possible issue

 

[Dereku]

For an aftermarket head unit? Those parking brake switches can be wired up to a manual switch easy. Test a ground before you apply power. It is the safe bet.

 

[airline tech]

 

[airline tech]

I may be able to get more in depth - if i knew what are you installing - Brand / Model Number, this would give the specs I am questioning

 

[hookem57]

Understood - but if the new head unit must see - 12 Volts to Ground (Circuit)
or just any completed circuit - is the question?

Point is you will need to try it or check the parking brake switch connector (key on) and see if it is 12 volts or 5 volts, its depending on what the head unit wants (specific 12 volts?)

We know that the voltage is provided by the BCM, open circuit = Light Off, pull the handle circuit is complete = Light On - So if the head unit (Req's a 12 volt input) then this signal (MAY NOT) work and it depends on if the BCM is providing 12 Volt Power on this circuit - (It may not be) and may only be pushing 5-Volts.

Basically tapping the circuit should simply work, but if you have issues - it may be due to the voltage output from the BCM and the answer to your question is - BCM Power looking for a ground to complete the circuit (switch closed) - so now it falls to what specific input does the after market head unit want or need for the input logic that the park brake is applied - a simple closed circuit or a voltage specific circuit - which the BCM may limit that requirement - so if you have issues of it not working (this will be the source of it)

Not trying to over complicate it - just pointing out a possible issue

Learn something new all the time on here. Thanks

 

[Ranger Pete]

Understood - but if the new head unit must see - 12 Volts to Ground (Circuit)
or just any completed circuit - is the question?

Point is you will need to try it or check the parking brake switch connector (key on) and see if it is 12 volts or 5 volts, its depending on what the head unit wants (specific 12 volts?)

We know that the voltage is provided by the BCM, open circuit = Light Off, pull the handle circuit is complete = Light On - So if the head unit (Req's a 12 volt input) then this signal (MAY NOT) work and it depends on if the BCM is providing 12 Volt Power on this circuit - (It may not be) and may only be pushing 5-Volts.

Basically tapping the circuit should simply work, but if you have issues - it may be due to the voltage output from the BCM and the answer to your question is - BCM Power looking for a ground to complete the circuit (switch closed) - so now it falls to what specific input does the after market head unit want or need for the input logic that the park brake is applied - a simple closed circuit or a voltage specific circuit - which the BCM may limit that requirement - so if you have issues of it not working (this will be the source of it)

Not trying to over complicate it - just pointing out a possible issue

Thank you for your input and information. Turns out, for my Sony head unit I am installing, connecting the parking brake lead to ground is all that is needed.

 

[Ranger Pete]

For an aftermarket head unit? Those parking brake switches can be wired up to a manual switch easy. Test a ground before you apply power. It is the safe bet.

Yes aftermarket Sony. I found out a simple connection to ground is all that is needed. Thank You!

 

[LB'sTremor]

Pete I would love to hear your review on it and maybe a link and pic?

LB

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