86 and 85 are the low amp circuit. 30 and 87 are the carrier wires to the load. The relay can be triggered using 86 ( + ) or 85 ( - ). Fuse on wire going to pin 30. Most relays are rated for 30amps so a 30 amp fuse would be the largest.
I run all my relays with the trigger switch on the ground side 85 so I don't have extra positive live wires running inside the car. I actually just branch off of the wire feeding pin 30 and jump it to pin 86.
Pin 87a ( center pin ) alternates opening with pin 87. When relay is energized its open ( no voltage ). When relay isn't triggered its closed ( battery + ). This is with most relays. Some relays are wired to trigger 87a and 87 at the same time but those aren't your common 5 pin relay.
I run all my relays with the trigger switch on the ground side 85 so I don't have extra positive live wires running inside the car. I actually just branch off of the wire feeding pin 30 and jump it to pin 86.
Pin 87a ( center pin ) alternates opening with pin 87. When relay is energized its open ( no voltage ). When relay isn't triggered its closed ( battery + ). This is with most relays. Some relays are wired to trigger 87a and 87 at the same time but those aren't your common 5 pin relay.
Relays typical use a solenoid to pull in a set of contacts to make/break the connection for your main power feed.
Here's a diagram that shows the internals of the relay. You have your Line (source) which is Pin 30, and your Load which is 87 (and 87A on a 5-pin relay shown below).
85 and 86 are your coil power and ground. This is what moves the amature to make/break connections between your load and your lines. This coil is very low current draw. Under 1amp typically but relays usually give this spec. Due to this low load, you don't need heavy gauge wiring for the coil. 18-22 will suffice. You can see wire size in the below diagram is smaller for the coil
I typically wire them like 90sickfox in which i'll tap off power nearby from something that has key on, or always on power, and then switch the grounds.
Here's a diagram that shows the internals of the relay. You have your Line (source) which is Pin 30, and your Load which is 87 (and 87A on a 5-pin relay shown below).
85 and 86 are your coil power and ground. This is what moves the amature to make/break connections between your load and your lines. This coil is very low current draw. Under 1amp typically but relays usually give this spec. Due to this low load, you don't need heavy gauge wiring for the coil. 18-22 will suffice. You can see wire size in the below diagram is smaller for the coil
I typically wire them like 90sickfox in which i'll tap off power nearby from something that has key on, or always on power, and then switch the grounds.
I know its less money to build one, but this place, ceautoelectric.com, has what I think is a nice Headlight relay kit #HRK2....
Wayne, to add to 5L5’s always good info, some relays, like the one in the picture, are wired to be normally open (off without trigger signal) or normally closed (on without trigger signal).
See the two terminals in the right of his picture. If you have one of these dual purpose relays, you will use the NO, normally open circuit wire to power something. The NC is better for a kill switch or logic circuit setup like the headlight buzzer I have ready to install.
See the two terminals in the right of his picture. If you have one of these dual purpose relays, you will use the NO, normally open circuit wire to power something. The NC is better for a kill switch or logic circuit setup like the headlight buzzer I have ready to install.
3-pin toggle switches with led usually require 12v on the third pin and then you switch the grounds, or vice versa.
Need to see switch to confirm though. I am making an assumption here
Need to see switch to confirm though. I am making an assumption here
Sorry if that was TMI. I assumed if someone can follow the surging idle checklist that the terminology for switches and relays should be easy enough to understand if not already common knowledge. Sometimes I read too much and do not type clearly enough,
The relays from Amazon are likely to be double function (NO/NC) with the extra terminal now like in the diagram. The basic horn and light relays from the FLAPS are still usually the single function, power to turn on relays. So those are the ones to use on lights, and the Heavier Duty ones for cooling fans.
Hey Wayne,
Here is a different video of a guy explaining relays and thin wires straight out.
Here is a different video of a guy explaining relays and thin wires straight out.