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How do you test for a broken relay?

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=5023
Printed Date: June 29, 2025 at 5:45 PM


Topic: How do you test for a broken relay?

Posted By: cpgoose
Subject: How do you test for a broken relay?
Date Posted: November 01, 2002 at 9:53 AM

Hi,

I have another post in "Security" about how when I jiggle some of the wires in my remote starter's relay satellite, the ignition power cuts on and off, and therefore messes up the ignition controlled features (that I have now turned off).

Anyway, I was wondering how to test these 5-terminal spdt (i think) relays?  I swapped out the relay I thought was broken with a new one, but it still did it (only not as much).  How do you actually test it with a DMM?  (I guess you have to give power and ground to two terminals and test for continuity?)

THANKS!!! posted_image




Replies:

Posted By: Velocity Motors
Date Posted: November 01, 2002 at 7:16 PM

Connect the (-) negative of the battery to one of the contacts of the inductor coil of relay ( either 85 or 86 ) and connect the (+) positive of the battery to the opposite contact of the inductor coil. You should immediately hear the relay "CLICK" as the swing arm switches between the normally closed contact pin to the normally open contact pin. If it clicks then the relay is working. If it doesn't do anything the relay is shot.



-------------
Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA




Posted By: Chris Luongo
Date Posted: November 02, 2002 at 8:33 AM

It might even be possible for a bad relay to still make clicking noises....although I've never seen one do so.  But you said you swapped it for a new one, and it's not likely you'd get two bad relays in a row, so I'd say it's probably not the relay.

More likely, one of the pins in the relay socket has a bad crimp, or there's a break in one of of the wires, but it's inside the insulation so you can't see it.

You could probably find a way to attach a test light to the suspected wire(s), and then jiggle them in various ways until you get the light to flicker.  After you figure out which wire is at fault, you'll probably want to slide the pin out of the socket, crimp a replacement one, and reinsert it.

I would say that if you're confident in your troubleshooting skills, and you have some patience, go ahead and find/repair the faulty wire.  But if you think it'll take you a long time to do this, it might be simpler to obtain a replacement relay satellite harness under warranty.





Posted By: cpgoose
Date Posted: November 02, 2002 at 12:41 PM

Cool, I'm definitely going to test the relays in the satellite.  For some reason, when I test the wires (either for continuity or resistance), it doesn't seem to "mess up" while I'm testing it.  If I jiggle the wires of certain relays, it clicks sometimes (which is the problem).  Then....when I test them, they don't seem to click anymore.  Grr. 

I was trying to slide the wire out of the female socket of the relay harness, and then maybe recrimp on a new terminal....but I couldn't get the wire out of the harness. 





Posted By: cpgoose
Date Posted: November 04, 2002 at 7:43 AM
When you test if the relay is broken......along with listening for the click, aren't you supposed to check for continuity as well?




Posted By: SnomanF150
Date Posted: November 06, 2002 at 8:05 PM
are you using t-taps or a scotch lock?  may be a bad connection.

-------------
George

David's Car Stereo

Baton Rouge, LA




Posted By: cpgoose
Date Posted: November 07, 2002 at 6:11 AM

nope...it's just one of those female harnesses like these:

posted_image





Posted By: SnomanF150
Date Posted: November 07, 2002 at 7:58 AM
i meant for powering those wires.. where are they giong to terminate at?

-------------
George

David's Car Stereo

Baton Rouge, LA




Posted By: cpgoose
Date Posted: November 07, 2002 at 9:12 AM
Oh...sorry.  They're just connected with the "threading the needle" type of connection....I split the wire open like an eye of a needle, and thread the wire though.  Wrap it in electrical and then zip tie it.





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