I want to wire up Aux Back Up Lights

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=13851
Printed Date: May 16, 2024 at 10:54 AM

Topic: I want to wire up Aux Back Up Lights

Posted By: 1999Expy
Subject: I want to wire up Aux Back Up Lights
Date Posted: May 22, 2003 at 2:27 PM

Hi folks I am new here. I am comfortable with wiring and have no trouble with connections but., I am a little fuzzy on the meaning of the numbers on relays (30,85,86,87a etc.) I have a 1999 Expedition and want to wire up auxiliary back up lights. I would like them to turn on when I put the vehicle in reverse. I understand that the reverse lights are the trigger for the relay. I have read the relay section/description. I am still confused. Could someone give me the knucklehead explanation as to what each number would actually be connected to? Thanks in adavance.

Replies:

Posted By: 1999Expy
Date Posted: May 22, 2003 at 2:48 PM

Would I be correct in saying that:

85: Revese light trigger

86: Ground

30: 12v+

87: Output+

87a: Output-

Posted By: hotrodelectric
Date Posted: May 23, 2003 at 11:02 AM

You would be, except you hook nothing up to 87a, unless you want something on continuously until the relay is switched on. The ground for your lamps are just that- to ground. Don't ground them to the ground leads from the factory lamps- you run the risk of overload. You can ground 86 to the same point as your lamps- maybe at the bolt used to ground the factory lamps to the chassis, if you can find it. You are OK tapping the 85 to the factory lamps output- you are taking less than 1/2 amp to switch on the relay.