timed headlights

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=78213
Printed Date: July 05, 2025 at 2:44 AM

Topic: timed headlights

Posted By: onifactor
Subject: timed headlights
Date Posted: May 23, 2006 at 9:01 PM

how would i go about using this diagram to power my headlights after the car has shut off for a short period of time?

posted_image

Replies:

Posted By: hotwaterwizard
Date Posted: May 26, 2006 at 9:03 AM

The time on this circuit is maybe 1 second maximum.

You need a transistor circuit to make the time longer.

https://www.electronics-lab.com/projects/oscillators_timers/013/index.html

posted_image Parts:

R1______________4K7 1/4W ResistorR2,R3___________1K  1/4W ResistorsC1____________100¡F  25V Electrolytic Capacitor (See Notes)D1___________1N4002 100V 1A DiodeQ1____________BC547  45V 100mA NPN TransistorQ2____________BC327  45V 800mA PNP TransistorP1_____________SPST  PushbuttonRL1___________Relay with SPDT 10A min. switch              Coil Voltage 12V. Coil resistance 150-600 Ohms

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: djfearny2
Date Posted: May 26, 2006 at 9:40 AM

use a timer relay. tap a wire off of the ignition

the ignition changes to ground so it will trigger the relay and all your doing is changing negative to possitive unless you have headlights that will work when your ignition is off. in that case you should check your headlight switch to see if it throws out a negative or possitive to control headlight factory relay. either way the dei 528t pulse timer relay will allow you to accomplish this. either possitive or negative for up 1.5 minutes i think. adjustable with a little screw driver.

if running a possitive setup
pin 30 constant fused
pin 87 output to lights
pin 86 tapped on to a true ignition
pin 85 tapped on to a true accessory wire.
pin 87a not used

negative setup same as above but pin 30 is grounded instead of constant fused.

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Jon
Installer/Help Technician
---coral springs florida---
mecp certification is not always needed. I have it and it has not helped me out at all. my experience out shines it.

Posted By: onifactor
Date Posted: June 08, 2006 at 10:58 PM

i think i'm going to go with that DEI timer relay. it's for a 95 honda civic, do you know whether that application is positive or negative?

could you possibly draw it all out for me? i seem to be in nitwit mode, for electronics, lately.

Posted By: cadillac_coupe
Date Posted: June 20, 2006 at 12:44 AM

Maybe you can use all the wiring taken out of a Cadillac with this feature. Would it work? Just a suggestion.

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cadillac_coupe