Relay heats up and closes when it shouldn
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=40495
Printed Date: May 14, 2025 at 7:31 AM
Topic: Relay heats up and closes when it shouldn
Posted By: vancouverbc
Subject: Relay heats up and closes when it shouldn
Date Posted: October 07, 2004 at 10:47 PM
I was trying to make the killer relay that is triggered by radio. It works ok with the 12 volts off of my jumpstarter but when I hook it up to the car's constant 12 volt it only works for about a minute and then heats up and does not work. By not work, i mean the relays close when i disconnect (i unplug wire going to radio 12v)the power from the radio. I do have a diode between 86 and 85 on one relay. I also have the diode going to radio. The terminals are abut an 1/8 of an inch apart on the relays. https://www.the12volt.com/relays/page2.asp ------------- 1991 240sx
alarm=model 2620.web central door locking system
Replies:
Posted By: vancouverbc
Date Posted: October 07, 2004 at 11:03 PM
I'm just wondering if I have created a capacitor in the circuit by how the two diodes might interact. I see that the diode that is in one of the relays is ground at 86 and positive at 85 which is the opposite of what it should be.
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1991 240sx
alarm=model 2620.web central door locking system
Posted By: draasch
Date Posted: October 07, 2004 at 11:43 PM
what are you trying to do????? ------------- Good Luck
David
Ace Security
813-376-9778
Tampa
Donate to the 12volt
Posted By: vancouverbc
Date Posted: October 08, 2004 at 2:18 AM
the relay that has the 12v at 30 has a diode between 86 and 85. anyway, 87-30 latches even though the lead from the radio is disconnected. something is heating up the relay and causing 87-30 to latch with no power to 85. ------------- 1991 240sx
alarm=model 2620.web central door locking system
Posted By: Teken
Date Posted: October 08, 2004 at 4:04 PM
Alright, so is the vehicle wired exactly as it is illustrated in the above image file??? Proper polarity has been observed with respect to the circuit??
How many amperes is the relay which you are applying to the circuit?? How large of a guage of wire are you using?
Regards
EVIL Teken . . .
Posted By: vancouverbc
Date Posted: October 08, 2004 at 4:29 PM
The main difference is the diode that is built into one of the relays. It's polarity is opposite of what it should be. I think the diode that goes to radio is rated 30 amps rather than 1 amp. Both relays are auto relays so should be rated at least 30 amps. I'm using 12v constant rather than ignition 12v at terminal 30. I will reverse the polarity of relay diode to see if this solves problem.
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1991 240sx
alarm=model 2620.web central door locking system
Posted By: vancouverbc
Date Posted: October 08, 2004 at 9:03 PM
well, I reversed polarity on the relay diode and the relay does not heat up but I still have the main problem. I see now that the relay sticks closed once it has been closed by the radio output. If I just hook up 12v to terminal 30, the relay does not close. I have to hook up the radio output to close relay. Once the relay closes, disconnecting the radio power does not open the relay. I completely cut the wire going to the radio. The relay only opens again when i disconnect the 12v at terminal 30.
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1991 240sx
alarm=model 2620.web central door locking system
Posted By: vancouverbc
Date Posted: October 08, 2004 at 9:11 PM
The wire is 18 guage. I soldered the wires to relay terminals using butane open flame. I guess relay was damaged.
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1991 240sx
alarm=model 2620.web central door locking system
Posted By: vancouverbc
Date Posted: October 08, 2004 at 9:39 PM
Ok, i just read a post by administrator eg the12volt. Apparently the relay is supposed to stay closed. i should not of hooked 30 up to constant 12v. should have hooked up to ignition. when i turn ignition off it will delatch.
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1991 240sx
alarm=model 2620.web central door locking system
Posted By: Teken
Date Posted: October 08, 2004 at 9:49 PM
vancouverbc wrote:
The wire is 18 guage. I soldered the wires to relay terminals using butane open flame. I guess relay was damaged.
This would be the second time which you have ignored my warnings about using a open flame on a electrical component.
Something else will be damaged in the vehicle in the future if you continue on this path.
Regards
EVIL Teken . . .
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