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Keyless Entry, Control Head Unit Power, PAC TR7

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=146361
Printed Date: March 29, 2024 at 2:09 AM


Topic: Keyless Entry, Control Head Unit Power, PAC TR7

Posted By: henno
Subject: Keyless Entry, Control Head Unit Power, PAC TR7
Date Posted: July 27, 2020 at 4:23 AM

I have a project surf van I am blinging out a bit. I just fitted an eBay keyless entry into the old girl after a mid range Sony head unit some Focals in the front some JBLs in the tailgate and a 10 inch sub under bed base.

The Chinese keyless entry radio has a spare temporary +ve pulse wire to trigger boot release. Could I use this pulse to trigger a latching relay to supply power to the head unit?

The idea is to be able to close the front doors and keep the tunes going while getting out boards and putting on wetsuits and shut tailgate and have the key fob lock all the doors and power down the stereo as I’m walking off. Vice versa when returning to the vehicle and unlocking it. I also like the idea of being able to locate my car in a parking lot by walking towards the sound of Metallica blaring.

Cheers from down under
Henno



Replies:

Posted By: i am an idiot
Date Posted: July 27, 2020 at 9:03 AM
Yes you can. If your keyless module can not be switched to a negative output on that wire, you can use this diagram but you will need to use a 5th relay to convert your positive out to a negative out. Simply replace the pictured push button switch with the 5th relay.

This

along with

this to convert positive to negative




Posted By: eguru
Date Posted: July 28, 2020 at 6:41 AM
Alternately get a PAC TR7 universal trigger module - about $20 on Amazon

https://catalog.pac-audio.com/index.php?controller=attachment&id_attachment=68




Posted By: henno
Date Posted: July 28, 2020 at 7:26 AM
This looks like good but it says it’s rated for 2 amps only. My head unit is hungrier than that.




Posted By: henno
Date Posted: July 28, 2020 at 7:31 AM
i am an idiot wrote:

Yes you can. If your keyless module can not be switched to a negative output on that wire, you can use this diagram but you will need to use a 5th relay to convert your positive out to a negative out. Simply replace the pictured push button switch with the 5th relay.

This

along with

this to convert positive to negative
This looks good for current draw but what is the value of the diode? I’m sure there is a spare neg output pulse.




Posted By: i am an idiot
Date Posted: July 28, 2020 at 7:24 PM
The red wire of your radio draws Milliamps of current. 1000ths of an amp.




Posted By: eguru
Date Posted: July 28, 2020 at 7:27 PM
henno] wrote:

This looks like good but it says it’s rated for 2 amps only. My head unit is hungrier than that.
You can use the TR7 to drive a relay to power your HU. You would typically only activate the HU via its ACC input whose current draw is minimal.




Posted By: henno
Date Posted: August 01, 2020 at 2:17 AM
OK. So I have a PAC TR7 on the way. Next question is can i then switch between my remote power supply triggered by the TR7 and the standard ignition power using a SPDT switch?

The reason is I leave my car unlocked at home (sleepy country town on acreage) and don’t want the head unit on all night at home so would like the advantage of flicking it back to normal so my ignition will kill it.

I’d prefer it to be a rocker switch but the only ones I seem to be able to find are on/off/on and I would prefer it to be on/on so it was one or the other with no off option in the middle.





Posted By: henno
Date Posted: September 26, 2020 at 7:38 AM
Has anybody got experience setting up one of these TR7s? There seems lots of advice on how to use them to watch Alpine DVD players while you’re driving.

I want to set up mine to latch the output on to turn on my stereo head unit when it gets 2 pulses from my remote entry receiver unit that go to my flashers/blinkers on unlocking the doors. Then unlatch to turn off head unit (1pulse from blinkers) when I lock doors.

I can set it up to go into Feature 13 by earthing the brown wire 13 times and getting that many flashes back but,,,,. The next step where I have to set it up so 2 pulses = on and 1 pulse = off is doing my bloody head in!

I tried feature 3 as a standard one pulse latch but none of the outputs from the keyless radio would get it on and off how I wanted every time. Feature 13 using the hazard/blinker pulses is good because there is a known difference between the on and off commands so I can’t get it out of sync if I double push a remote button.




Posted By: henno
Date Posted: October 03, 2020 at 7:22 AM
So my mad scheme to have my head unit turn on or off using my keyless remote works with a glitch.

I have the PAC TR7 set up to be triggered via its green pos input wire connected to the brown outputs that supply one flash to turn signals for lock and two for unlock.

Problem became apparent when I took it for a drive and put my turn signal on and it turns off my stereo! Hilarious really.

Is there any way the brown outputs from the keyless entry radio (still connected to input wire of TR7) can still pass their pulses to the lights but the inputs on that same wire coming from my hazard button or turn signal stalk don’t get their pulses back to the TR7?

Would it be as simple as a diode in-line? If so what value or is their a preferred auto component for this task?

posted_image




Posted By: eguru
Date Posted: October 03, 2020 at 10:54 AM
Insert a rectifier in series with the wire(s) going to your vehicle's turn signals. Connect the anode to those wires and the cathode to the junction of the BN wire from your RS and the GN trigger wire going to the TR7.

A 10 Amp rectifier should be sufficient (especially if you are using LED bulbs). A T10A60L should work fine.




Posted By: henno
Date Posted: October 03, 2020 at 7:09 PM
How do I get a lone component like that inline with car wiring though? I could drop one into the holes of a bread board andsolder one in but never had the need to put a lone component into car wiring. Soldering wires straight onto diode terminals would be pretty ugly even for me.

I can find spade fuse shaped diodes that would fit into an inline fuse holder.





Posted By: henno
Date Posted: October 03, 2020 at 10:42 PM
Thanks mate. I crimped the diode onto bullet terminals an put heatshrink on the whole thing. Works a treat now.

posted_image





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