radio on until door open

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=136948
Printed Date: May 02, 2024 at 7:44 AM

Topic: radio on until door open

Posted By: linkarmy09
Subject: radio on until door open
Date Posted: July 14, 2014 at 7:50 AM

hello have a question regarding my radio on until door open. so im using the diagram
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Everything used to work fine and loved the fact that my radio would stay on until i opened my door. Now i have just installed an alarm on my car (95 honda accord lx) and what it does is as soon as i turn the car off and proceed to remove the keeys it activates my interior lights making my relays think the door is open so the radio turns off. Could anyone here suggest a way to isolate this to where the relays only activate when the door is opened regardless of the interior lights? Any help in general would be greatly appreciated, thank you.

Replies:

Posted By: the12volt
Date Posted: July 14, 2014 at 8:52 AM

You will need to diode isolate a door trigger/pin switch from the common door trigger/dome light lead, then connect the relay on the door trigger/pin switch side of the diode. The band on the diode will be facing the isolated door trigger/pin switch.

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Posted By: linkarmy09
Date Posted: July 14, 2014 at 9:13 AM

i believe im understanding but since i am pretty new at this and a quick diagram would really help if possible. im just getting started with the whole electronics and diodes is not something i have used before.

Posted By: the12volt
Date Posted: July 14, 2014 at 9:54 AM

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Posted By: linkarmy09
Date Posted: July 14, 2014 at 2:34 PM

thank you so much this would greatly help

Posted By: the12volt
Date Posted: July 14, 2014 at 2:54 PM

You're welcome.

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Posted By: davep.
Date Posted: July 14, 2014 at 11:34 PM

I'm not familiar with Hondas. I don't know if they have dome light relays or not.

If they don't the diode will have to be large enough to carry the entire current of the dome lights. The 'standard' 1 Amp diode that installers use will probably have a short life if it carries more than a trigger current.

The other thing with using just the one door pin switch is that occasionally you won't cancel the RAP if you get out on the passenger side.

I've run into the OP's situation too. Usually in 80's-90's GM's where turning on the dome lights with the dash switch cancels the RAP. Annoying. I use an additional relay to isolate the pin switches from the dome-light circuit. These earlier GM's don't have dome light relays, and dome light circuit current of about 3.5 amps. Using a relay is more reliable.

Posted By: davep.
Date Posted: July 14, 2014 at 11:39 PM

You could also program the alarm for "no dome lights with ignition off".
DEI has had this as a programmable feature for a long time.

Posted By: linkarmy09
Date Posted: July 15, 2014 at 7:32 AM

davep. wrote:

You could also program the alarm for "no dome lights with ignition off".
DEI has had this as a programmable feature for a long time.

i belive i did see this option on my alarm, might just be the easiest will definately will have to look at the manual once again. I have a python 5106 alarm/remote start by the way.

Posted By: linkarmy09
Date Posted: July 16, 2014 at 9:21 AM

Read through the manual and to disable the dome light with ignition off is not an option on my alarm. I was thinking would it not be easier to isolate the door trigger to the realy that keeps the power to the accesories. Not sure if i make myself clear. What i mean is is there a way to make it to where the door switch has two signals isolated from each other (As if there was two separated switches) and have the regular wire to the alarm and run a second to the accessoreis on until door open relay?

Posted By: davep.
Date Posted: July 16, 2014 at 10:32 AM

linkarmy09 wrote:

is there a way to make it to where the door switch has two signals isolated from each other (As if there was two separated switches) and have the regular wire to the alarm and run a second to the accessoreis on until door open relay?

Go back to Plan A. Admin's diagram for diode isolation. If a 1 Amp diode burns up, post again, and someone will come up with a sketch for using a relay instead.

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Posted By: the12volt
Date Posted: July 16, 2014 at 10:57 AM

The diagram shows isolating a single door trigger (driver's door) and the trigger to the relay from the rest of the triggers. As davep pointed out, a 1 amp diode would likely be too small for the way I have it drawn.

If you placed the diode (1 amp) on the alarm door trigger lead instead with the cathode (stripe) side away from the alarm, it would prevent the alarm from turning on your dome light, your original set up would continue to work as it did, and the door triggers would still trigger the alarm. posted_image

If you do not want to disable the dome light from coming on with the alarm, cut the lead going to the dome light from all door triggers and wire to your existing relays as shown below. No diodes needed.
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Posted By: linkarmy09
Date Posted: July 16, 2014 at 3:43 PM

ahh the magic of relays. Definatly will attempt this options this weekend and see if i can my setup working.