relay blocking or use of a diode?

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=100252
Printed Date: June 24, 2025 at 5:41 AM

Topic: relay blocking or use of a diode?

Posted By: brakisshuro
Subject: relay blocking or use of a diode?
Date Posted: December 20, 2007 at 12:16 PM

So I have a 03 dodge. There is a 4.5v rest resistance on the parking light circuit. I put a 1.4k resistor on it, but i am getting feedback and it is not only clicking on my parking lights when I click lock or unlock, but it is also switching on my headlamps. help?

BTW it is a -200ma trigger to -parking lights

Replies:

Posted By: techman93
Date Posted: December 20, 2007 at 10:49 PM

03 dodge what? Caravan, Sebring? What unit did you put in also info that may help.

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The wire I'm test'n isn't doin' what it's supposed to be doin'... I am so glad I printed that tech sheet, with the wrong info.
Do it right the first time... or I might have to fix it for ya

Posted By: brakisshuro
Date Posted: December 21, 2007 at 11:07 AM

compustar 1wam s, 03 dodge 2500 diesel

Posted By: tedmond
Date Posted: December 21, 2007 at 5:03 PM

u would use a relay and a diode. If your parking light output is only 200mA, i suggest you use a relay. But im sure compustar have built in relays for parking lights.

if you dont have an onboard relay from the compustar, connect up a relay like so.

85 - constant 12v
86 - parking light output from starter
87 - Ground (high current) with 1.4k ohm resistor.
87a - cut parking light wire, connect from Lamp Switch Side.
30 - to parking light wire (end that is cut)

that way, when you dont use your remote start, the fucnition of the factory lights can be used accross the relay. Once the relay is active (from lock or unlock), the relay is triggered to send 1.4k ohms to your parking light wire.

Posted By: tedmond
Date Posted: December 21, 2007 at 5:05 PM

crappy, forgot to mention. Place a diode across terminal 85 and 86. Canthode to 85 and anode to 86. (prevents feedback on device u connect to from the relay coil)

Posted By: brakisshuro
Date Posted: December 23, 2007 at 12:20 PM

your the man, thank you for the help. This forum is great. Last question, is there a specific diode I should use?

Posted By: tedmond
Date Posted: December 25, 2007 at 9:18 AM

parking lights are high current drawing devices and can load out the coil. Well use any diode that you have.

any of these will work just fine

1N4002
1N4003
1N4004

rectifing diodes. you can use any of those, but if u would like to play it safe, go with the 1N4004. that is what i use most on my installs for isolating circuits.

Posted By: brakisshuro
Date Posted: January 03, 2008 at 8:59 AM

thank you for all your help. I really appriciate it

Posted By: KPierson
Date Posted: January 03, 2008 at 9:11 AM

tedmond wrote:

crappy, forgot to mention. Place a diode across terminal 85 and 86. Canthode to 85 and anode to 86. (prevents feedback on device u connect to from the relay coil)

The diode wouldn't be necessary here. Any device that is designed to drive a relay (ie 200mA output, ) will have the diode integrated with the drive circuit.

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Kevin Pierson