Relay testing

MikeT · Unread post by **MikeT** » 04 Apr 2009, 12:09

I wanted to test a five pin relay. Usually I would energise the coil, listen for the click then test the switched pins for continuity.

However, when I touched the coil (85 & 86) with 12v it sparks and no click can be heard. I don't want to leave 12v connected in case it shorted my battery. I did read that anything below 50 ohms across the coil indicates it's duff. I get 0.6ohms. Can anyone confirm it's a dead relay given the info above please?

addo · Unread post by **addo** » 04 Apr 2009, 12:34

Sounds like it's welded itself on. Cooling fan relay?

Cheers, Adam.

MikeT · Unread post by **MikeT** » 04 Apr 2009, 13:28

It's not the cooling fan relays no, they've already been tested as good. It's a spare I had - always worth keeping spares but not if they're kaput.

Clogzz · Unread post by **Clogzz** » 04 Apr 2009, 14:59

anyone confirm

Confirming that the coil is shorted, and probably a crispy black.

DC operated relay coils have high resistance, and I’ve got the figure of 200 Ohms in mind.

MikeT · Unread post by **MikeT** » 04 Apr 2009, 16:19

Ok, thanks for confirming my suspicions.