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wiring fog light ’latch’ relay

Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=114412
Printed Date: May 18, 2025 at 10:22 PM


Topic: wiring fog light ’latch’ relay

Posted By: garethramsay
Subject: wiring fog light ’latch’ relay
Date Posted: June 12, 2009 at 2:31 PM

Hi,

Can anyone help with me wiring in a fog light switch? I have a fog switch which is a push-to-make-contact switch... when pressed in it makes a contact, when your finger comes off, there is no contact. I want to use this for my front fogs as it is a standard fog switch which fits the hole, but from a later car model unfortunately.

The switch has a wire coming out which will carry a current for the short time the switch is pressed - and this same current must turn the relay on and then turn the relay off. I have been advised I need a 'latching' relay and an electrician told me that a VW Beetle from the 70s has just such a relay for turning dipped lights into full beam.

I have sourced a relay (picture below) from a VW Beetle which *I think* is the correct one but am quite out of my depth with this kind of relay! Can anyone help with wiring this in to the switch?

posted_image

I understand where the 56a and 56b (I think it says b!) must connect to - one to the fog light relay and one should be empty (for off).

This leaves 56, 30 and S - one must be a permanent 12v (I can grab this from the 12v into the switch) would this be 56? One must be the output from the switch (either 30 or S)... is the other earth? I cannot understand from the diagram how 30 and S work!

Any help you can offer would be hugely appreciated!

Thanks,

Gareth



Replies:

Posted By: Ween
Date Posted: June 12, 2009 at 9:11 PM

hi,

terminal S connects to the pushbutton switch,

terminal 30 connects to + 12 volts battery,

terminal 56 connects to +12 volts, can be ignition or parking lamp, will insure fog lights won't be left turned on.

terminal 56b connects to the fog lamp relay, + 12 volts out

terminal 56a will be unused.

hope this helps

m





Posted By: garethramsay
Date Posted: June 13, 2009 at 1:48 AM
Thanks Ween! I assume I can use a 12v from the ignition for both the 12v? I have one of these routed in behind the switches already...

Gareth




Posted By: Ween
Date Posted: June 13, 2009 at 2:03 AM

yes, ignition for both will work fine

m





Posted By: garethramsay
Date Posted: June 13, 2009 at 6:30 AM
Hi Ween,

I purchased a relay from an old VW specialist, however the wiring is slightly different to the one I posted above:

posted_image

Does this make any difference to the way you suggest wiring it up for the purposes of my fog light? Should I go with the same pins?

Thanks,

Gareth




Posted By: garethramsay
Date Posted: June 13, 2009 at 6:35 AM
Sorry fopr the multiple posts, I can't edit my last one.

From the new diagram, it looks as though 56a and 56b will both be receiving power at all times, no matter which way the relay sits...

Gareth





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