Remote trunk release w/aftermkt. alarm
09-15-2007, 07:53 AM
#1
Remote trunk release w/aftermkt. alarm Are there any decent aftermarket alarm systems out there that come with remote fobs that have a remote trunk release? If so, have any of you tried them and are they worth your time/money? My car's original owner was a cheapass (or something) and didn't buy the car with an alarm system - second owner had a cheapass alarm system installed and it's sort-of lame. :\
09-15-2007, 11:03 PM
#2
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almost any alarm has an auxialry output that can be used to pop the trunk. i know all dei products have them, also prestige. Its just a matter of hooking up a relay to the trunk release wire and the auxilary output. If you do it yourself, dont connect to the wire at the switch, connect at the out side of the bcm in the passanger kick panel. The switch "goes to sleep" after the doors are closed w/o igntion on for a few minutes
09-16-2007, 09:30 AM
#3
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I have a Viper system that pops the trunk, but the button on the remote works like the trunk button on the interior. I am just assuming that was Best Buy's doing, three times and still couldn't get it right.
08-27-2008, 05:40 PM
#5
TTT
I took my Viper responder alarm back to the dealer to ask why it won't pop the trunk. It will work after you get out of the car for about a minute. After a minute or two, the aftermarket remote will not pop the trunk. You have to open the door to get the trunk to pop.
They showed me that with the window rolled down, after a minute or two the trunk pop button inside of the car will not work either. The dealer said it has something to do with the BCM. The alarm is sending a sigal but something in the cars wiring is stopping it from working. How do I have them fix this.
I took my Viper responder alarm back to the dealer to ask why it won't pop the trunk. It will work after you get out of the car for about a minute. After a minute or two, the aftermarket remote will not pop the trunk. You have to open the door to get the trunk to pop.
They showed me that with the window rolled down, after a minute or two the trunk pop button inside of the car will not work either. The dealer said it has something to do with the BCM. The alarm is sending a sigal but something in the cars wiring is stopping it from working. How do I have them fix this.
08-28-2008, 01:24 PM
#7
They probably wired the alarm to the same wire as the dash button. Unfortunately, the BCM goes to sleep after a few minutes so it doesn't respond to external signals like that.
The factory switch is a grounding switch - it provides ground on the black with white signal wire when the button is pressed. What they need to do is change the wiring so that the alarm sends a power (positive) pulse to the brown wire (pin D4 in connector C3) at the BCM. This bypasses the BCM and sends the pulse directly to the hatch release relay so it will work even after the BCM has gone to sleep.
The factory switch is a grounding switch - it provides ground on the black with white signal wire when the button is pressed. What they need to do is change the wiring so that the alarm sends a power (positive) pulse to the brown wire (pin D4 in connector C3) at the BCM. This bypasses the BCM and sends the pulse directly to the hatch release relay so it will work even after the BCM has gone to sleep.
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08-28-2008, 09:06 PM
#8
What they told me is that it is always sending a postive signal. When I press the button, it sends a ground signal to make it work. If this is the way that they have it installed, will doing it your way still work? Or will the wires that they have to tap into change? I plan on taking this thread into them and telling them to modify it to work.
08-28-2008, 09:26 PM
#9
The existing dash button has two wires - one from the BCM and the other straight to ground. When the button is pressed, it completes the circuit from the BCM to ground signaling the BCM to send a positive pulse on another wire to activate the hatch release relay.
If they tapped into the factory switch wiring with the alarm then the alarm must be providing an alternate ground on that circuit - the alarm then does the same thing the button would do, ground the signal wire to the BCM to get it to trigger the relay. A power feed to that circuit wouldn't do anything useful.
When triggered by the factory switch or the alarm, the BCM sends a positive pulse on the brown wire which energizes the coil of the hatch release relay which then sends power to the release mechanism. To get the alarm to do the same, just change the negative pulse on the switch wire to a positive pulse on the hatch relay coil wire. That will bypass the BCM function and release the hatch even after the BCM has gone to sleep.
Here is the schematic:
If they tapped into the factory switch wiring with the alarm then the alarm must be providing an alternate ground on that circuit - the alarm then does the same thing the button would do, ground the signal wire to the BCM to get it to trigger the relay. A power feed to that circuit wouldn't do anything useful.
When triggered by the factory switch or the alarm, the BCM sends a positive pulse on the brown wire which energizes the coil of the hatch release relay which then sends power to the release mechanism. To get the alarm to do the same, just change the negative pulse on the switch wire to a positive pulse on the hatch relay coil wire. That will bypass the BCM function and release the hatch even after the BCM has gone to sleep.
Here is the schematic:
09-07-2008, 06:57 PM
#11
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when you put the alarm in you use a pcm wake up wire stay away from the best buy and circut city i use to instal at a couple high end shops we tried a couple cc peple had to fire them because they had very little experiance in highend auto and alarm like clifford
09-20-2010, 10:04 PM
#13
could i please get a write up or something along those lines (pictures!) of how this is supposed to be done properly? the auxiliary button on my clifford matrix rsx 3.5 does not open the trunk all the time, which makes me think that the bcm is going to sleep.
i am an electrical dummy but I do know that the way that it is set up now. i have a plastic t (crimp i guess) that taps into the wire that comes right off of the trunk release switch. i would provide picture of what is going on but my car is down and at my friends place.
i got my soldering iron ready to go.
any help would be greatly appreciated.
i am an electrical dummy but I do know that the way that it is set up now. i have a plastic t (crimp i guess) that taps into the wire that comes right off of the trunk release switch. i would provide picture of what is going on but my car is down and at my friends place.
i got my soldering iron ready to go.
any help would be greatly appreciated.
09-21-2010, 07:15 AM
#14
Put down the soldering iron and step away from the vehicle. 
Seriously, the instructions and diagram above are complete and accurate. I understand that you aren't familiar with wiring but perhaps that should make you consider getting someone else to do it. Improperly done wiring can lead to burning your car to the ground.
That said, you need to check the instructions for your alarm. It is currently set up to trigger the hatch release using a negative (ground) pulse on the wire connected to the hatch switch in the dash. You need to find a way to produce a positive pulse instead. Usually that will be done either with a separate wire from the alarm "brain" or by a switch in the "brain" that will change the polarity of the existing wire. You need the manual to find out which.
Once you find a wire producing a positive pulse for hatch release, connect it to the brown wire in position D4 of the large blue connector at the BCM. The brown wire is between a black with white wire and a pink wire in the connector. Don't cut the brown wire - just splice into it. Be sure to remove the existing alarm wire from the dash hatch release and tape it up if not used.
Seriously, the instructions and diagram above are complete and accurate. I understand that you aren't familiar with wiring but perhaps that should make you consider getting someone else to do it. Improperly done wiring can lead to burning your car to the ground.
That said, you need to check the instructions for your alarm. It is currently set up to trigger the hatch release using a negative (ground) pulse on the wire connected to the hatch switch in the dash. You need to find a way to produce a positive pulse instead. Usually that will be done either with a separate wire from the alarm "brain" or by a switch in the "brain" that will change the polarity of the existing wire. You need the manual to find out which.
Once you find a wire producing a positive pulse for hatch release, connect it to the brown wire in position D4 of the large blue connector at the BCM. The brown wire is between a black with white wire and a pink wire in the connector. Don't cut the brown wire - just splice into it. Be sure to remove the existing alarm wire from the dash hatch release and tape it up if not used.
09-22-2010, 07:29 AM
#16
I am not aware of an online tutorial for wiring schematics. However, a great general electricity and electronics tutorial is at Basic Car Audio Electronics. It starts with basic electricity, Ohm's Law, etc. and then moves on to switches, relays, capacitors and more, then finally gets into speakers, amps and other audio equipment.
Once you have the background understanding of electrical circuits, you only have to learn what schematic symbols represent to be able to read the "road map" of an electrical diagram.
In the schematic above, 12V power is coming into the circuit through the fuses at the top. On the right side, you'll see that power from the PWR ACCY fuse (hot at all times means unswitched battery power) flows down to the switch side of the release relay. When that relay is tripped, power then flows through the switch to the hatch release motor and from there to ground (G400 is a ground on the rear valance panel). The relay is controlled by the BCM - the brown wire that is circuit 253 in the diagram. The BCM gets its power from the COURTESY fuse at the top of the page. When the BCM gets a signal to release the hatch (somebody presses the switch on the dash which connects circuit 1576 to ground G200), it sends a power pulse through the brown wire 253 to the coil side of the relay causing it to trip and close its internal switch sending power to the hatch release motor.
Once you have the background understanding of electrical circuits, you only have to learn what schematic symbols represent to be able to read the "road map" of an electrical diagram.
In the schematic above, 12V power is coming into the circuit through the fuses at the top. On the right side, you'll see that power from the PWR ACCY fuse (hot at all times means unswitched battery power) flows down to the switch side of the release relay. When that relay is tripped, power then flows through the switch to the hatch release motor and from there to ground (G400 is a ground on the rear valance panel). The relay is controlled by the BCM - the brown wire that is circuit 253 in the diagram. The BCM gets its power from the COURTESY fuse at the top of the page. When the BCM gets a signal to release the hatch (somebody presses the switch on the dash which connects circuit 1576 to ground G200), it sends a power pulse through the brown wire 253 to the coil side of the relay causing it to trip and close its internal switch sending power to the hatch release motor.
