SPDT Relays

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=18154
Printed Date: July 20, 2025 at 1:36 AM

Topic: SPDT Relays

Posted By: ronnyd8719
Subject: SPDT Relays
Date Posted: August 27, 2003 at 11:28 AM

I just put in an alarm and electric door locks in my Mazda B3000. Now I have a battery drain problem. It is a slow drain. If I don't drive the truck for two days I will have to jump start it. I have check all the wires and all seem to be ok. I did notice the SPDT relays are warm. So I figure they are drawing power all the time. Is this normal. I did check the wiring and it is the way is should be and the locks work like it should. I need to get this battery draw figured out. Any help would be welcome. Thanks Ron

Replies:

Posted By: italnpimp59
Date Posted: August 27, 2003 at 2:59 PM

what kind of lock system do u have....and how exactly is the keyless entry wired up?

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Posted By: ronnyd8719
Date Posted: August 27, 2003 at 5:33 PM

I have added on door lock actuaators.

Two relays

One for locking and one for unlocking

unlocking relay 85 unlock output. 87 12v constant. 86 12v constant fused. 30 door unlock wire motor side.

Lock relay 85lock output. 87 12v constant. 86 12v constant. 30 door lock wore motor side.

Thanks for the help. I need it.

Later Ron

Posted By: italnpimp59
Date Posted: August 28, 2003 at 7:57 PM

well SPDT relays always draw 130 milliamps of current. but thats not enough to kill your battery. unless you have an old battery that seriously needs to be replaced! is your keyless entry working correctly? if not, what polarity is coming from the pulse from the alarm brain? and what polarity do the lock/unlock wires need? oh yeah and the lock actuators that you installed...are they 2 or 5 wire?

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Posted By: auex
Date Posted: August 28, 2003 at 9:40 PM

Relays only draw current when they are active. The relays are 5 wire because he added the actuators. Your relays should be wired like this. posted_image

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Posted By: ronnyd8719
Date Posted: August 29, 2003 at 7:57 AM

Yes that is the way my relays are wired. Just like the pic in the post before this one. The locks work right. Will the relays stay a little warm.
I had my battery and system checked all is good. The was bought 1-2002. not that old.

Would anyone say it is safe to use the SPDT Relay setup on this website to use as a remote car starter?

Thanks for the help.