newbie needs relay testing help?
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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=14966
Printed Date: May 29, 2024 at 2:40 AM
Topic: newbie needs relay testing help?
Posted By: steveo29
Subject: newbie needs relay testing help?
Date Posted: June 15, 2003 at 8:14 AM
could someone please help me to test this relay...i have terminals 30,85,86,87,87a....if i manualy close the relay with my finger the devise works....im unsure what wire is the trigger and how to check it...i suspect it i fine as i also have a new one that does not cure the prob thank you for any help
Replies:
Posted By: xetmes
Date Posted: June 15, 2003 at 8:48 AM
huh? if you want to see if it is functional use an ohm meter to check between 85 and 86, it should be around 95 ohms. check 30 and 87a it should be 0 ohms, check 30 and 87 it should be infinite ohms. then give 12 volts between 85 and 86, you should hear it click, then ohm out 30 and 87a, should be infinite, 30 and 87 should be 0.
Posted By: steveo29
Date Posted: June 15, 2003 at 8:57 AM
what do you mean 12v between 85 and 86...does that mean + to one and - to the other with the ign on in the car all terminal are 12+ apart from87a and 87....should 87 power up sorry if this is annoying for a pro ,but i cant figre it
Posted By: MielGibson
Date Posted: June 15, 2003 at 10:46 AM
steveo29 wrote:
what do you mean 12v between 85 and 86...does that mean + to one and - to the other
with the ign on in the car all terminal are 12+ apart from87a and 87....should 87 power up
sorry if this is annoying for a pro ,but i cant figre it
Click h e r e
for more help.
Posted By: xetmes
Date Posted: June 15, 2003 at 11:19 AM
you just have to know how a relay works, if you apply 12 V to a coil of wire it creates a magnetic field, by creating the magnetic field in a relay a small metal contact becomes attracted to it, therefore it moves, this piece of metal is attatched to pin 30, the 2 ends of the coil are pins 85 and 86. the metal tab that is attatched to pin 30 rests normally at pin 87a, when it moves because of the magnetic field it goes to pin 87. think of it as a switch (between 30 and 87) but instead of using your finger to control it you use voltage on the coil (85 and 86). So if you attach 12V (positive to one terminal, negative to the other), it will move that matal contact and you will hear a 'click'. hope that helps
Posted By: steveo29
Date Posted: June 15, 2003 at 11:34 AM
thanks for the help...i'll go have a look at it 
Posted By: steveo29
Date Posted: June 17, 2003 at 1:14 PM
ok i tested as in xetmes explanation...... nothing at term 87 on my old and brand new relay....everything else is as it should be.....am i safe to assume theyre both dud thanks for the help
Posted By: xetmes
Date Posted: June 17, 2003 at 1:17 PM
What do you mean nothing? Vlotage you mean? You will only get voltage at 87 if the coil is energized and you have voltage at pin 30, i doubt they are bad.
Posted By: steveo29
Date Posted: June 17, 2003 at 1:23 PM
i have 12v at pin 30....when i turn the ign on everything except 87 and 87a goes live.....if i manualy close the relay then 87 goes live 12v and my abs pump works thanks for helping
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