Relay wiring
Senior User
Joined: Apr 2008
Posts: 365
Likes: 4
From: Round Rock, TX
On my 2004 it was a black w/ pink stripe wire on the chassis wiring. It was probably a 18-20ga wire.
https://www.cvpi.com/truckbbas/topic...lectrical.html
Those PDF's should help you.
http://www.accessconnect.com/trailer_wiring_diagram.htm
https://www.cvpi.com/truckbbas/topic...lectrical.html
Those PDF's should help you.
http://www.accessconnect.com/trailer_wiring_diagram.htm
Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
If you have a relay with the numbers marked on it, here's the cheat sheet.
85 coil ground
86 coil positiver (these two can be switched, unless there is a spike suppression diode in it.)
30 is the common pole (it flips between 87 and 87a)
87 is the switched position (when the coil is hot, 30 and 87 are connected)
87a is the at rest position (when the coil is not powered, 30 and 87a are connected.)
So you need to ground the 85 terminal and run the 86 to the backup 12+v wire. the relay will now click.
Then it's 30 to the lights and 87 to the battery/fuse.
85 coil ground
86 coil positiver (these two can be switched, unless there is a spike suppression diode in it.)
30 is the common pole (it flips between 87 and 87a)
87 is the switched position (when the coil is hot, 30 and 87 are connected)
87a is the at rest position (when the coil is not powered, 30 and 87a are connected.)
So you need to ground the 85 terminal and run the 86 to the backup 12+v wire. the relay will now click.
Then it's 30 to the lights and 87 to the battery/fuse.
