spacer spacer spacer spacer

Relay To Turn Lights Off When Starting

Post ReplyPost New Topic
< Prev Topic Next Topic >
Gold - Posts: 4,913
Gold spacespace
Joined: November 03, 2008
Location: Australia
Posted: January 17, 2011 at 2:51 PM / IP Logged  
You can't fry anything...
The lighting relay will have +12V ate each end, or 0V at each end, or 0V & +12V across either end. (Hence add a diode if you don't want the starter to turn on the lights with the headlights/foglights off etc.)
The lighting relay now merely grounds thru the starter solenoid instead of body/chassis.
Hence the lighting relay's "ground" can now be ground thru the much lower resistance starter solenoid, else +12V when cranking.
I don't think a connection diagram is required for "reconnect lighting relay coil ground to starter solenoid signal (at starter preferably, else from IGN switch). Or is it?
But you need to ensure the lighting relay has no diode across the coil to suppress spikes UNLESS you fit the blocking diode from the starter solenoid so it cannot "energise" the lighting relay if its normal #86 is connected to other circuits else is ground (instead of floating or +12V).
In fact, the diode from starter to lighting solenoids/coil may be best. Line (Kathode) end towards the lighting relay.   
Whilst a circuit diagram as I usually draw is IMO useful, I don't see that the normal the12volt style of (hardware) connection diagram helps over the above descriptive.
But that's just my opinion. Plus a diagram will have to wait....
Member - Posts: 6
Member spacespace
Joined: January 15, 2011
Location: United Kingdom
Posted: January 17, 2011 at 3:09 PM / IP Logged  

Thanks for the help, I've never considered the option of using a +12v supply to earth/ground a component before, even though I've completely rewired cars before, and installed alarm systems, stereos and many other components, as these normally just require a supply nd earth/ground and signal wires for other components. I'll definitely use your suggestion.  The aftermarket relay and loom available to buy at large cost not only isolates the lights before and during starting, but prevents the lights from coming on until the high/low switch is flicked, then the lights remain live until the ignition is switched off,  would that be a latch relay set up??

Page of 2

Sorry, you can NOT post a reply.
This topic is closed.

  Printable version Printable version Post ReplyPost New Topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

Follow Follow on Facebook
Thursday, June 13, 2024 • Copyright © 1999-2024, All Rights Reserved Privacy Policy & Use of Cookies
Disclaimer: *All information on this site ( ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.

Secured by Sectigo spacer spacer spacer
Top spacer spacer