AU Ford Falcon - SPUD Project

Relays - General Information

Relays - General Information

Below is a simple guide to different types of relays

None of this is special information specific to the AU Falcon, but for the sake of brevity and convenience, only relays included in the model are listed here

4-Way Mini-ISO Relay

Layout

87
86		85
30

Functionality

These relays represent the simplest form of automotive relay. Put simply, when a 12v signal is provided from pin 86 to 85, then the 12V constant power from pin 30 will be connected to pin 87 with any 12V power present.

Example - Simple Auxiliary device

• Connect low amperage power to pin 86
• Connect high amperage power to pin 30
• Connect a switch from pins 85 and 86
• Connect positive wire from auxiliary device (e.g. light) to pin 87
• Connect ground to auxiliary device
• Done

5-Way Mini-ISO Relay

Layout

87
85	87a	85
30

Functionality

These relays are quite similar to the 4-Way Mini-ISO relays, however they have another pin available, for when the relay is not switched. As a result, this is probably best not to be used for a circuit that is constantly powered, as it will likely cause a constant power leak from the car battery, even when off.

Example - switching between exclusive systems

• Connect low amperage power to pin 86
• Connect high amperage power to pin 30 (switched recommended)
• Connect switch from pins 86 to 85
• Connect auxiliary device #1 positive wire to pin 87
• Connect auxiliary device #2 positive wire to pin 87a
• Connect ground to auxiliary devices
• Enable switch between pins 86 and 85 to deactivate auxiliary device #2 and activate auxiliary device #1
• Disable switch between pins 86 and 85 to deactivate auxiliary device #1 and enable auxiliary device #2
• Done

4-Way Micro-ISO Relay

These relays are not particularly common compared to the mini-ISO counterparts, however they function in a very similar way. Unfortunately the pin numbers are also changed on these relays, likely due to the difference in standards

the OEM relays from the AU Falcons appear to be 5-Way Micro-ISO relays with the alternate output pin, pin 4, cut off.

Layout

3
5
2	1

Functionality

These relays function exactly the same as the 4-Way Mini-ISO relays. Put simply, when a 12v signal is provided from pin 2 to 1, then the 12V constant power from pin 3 will be connected to pin 5 with any 12V power present.

Example - Simple Auxiliary device

• Connect low amperage power to pin 2
• Connect high amperage power to pin 3
• Connect a switch from pins 2 and 1
• Connect positive wire from auxiliary device (e.g. light) to pin 5
• Connect ground to auxiliary device
• Done

a 5-way relay for the same Micro-ISO size would function more like the 5-way Mini-ISO relay, however it is not noted as it is not relevant to this project

3-Way Flasher Relay

Functionality

There is only one of these types of relays present in the AU Falcon, used for the Indicator bulb circuit within the vehicle. Power is quite simple with a caveat. When power is supplied between 12V pin 49 and the Earth on pin 31, the positive output of pin 49a will flash depending on the wattage required for the pin. The important caveat is simple: the OEM flasher relay is designed for 2/4x21W globes, and as such nominal operating wattages are either approx. 42W total or 84W total.

Layout

49a	49
	31

Example - Custom work flasher lights

• Connect high amperage power to pin 49 (switched recommended)
• Connect ground to pin 31
• Connect positive for auxiliary system to pin 49a (42/84W circuit recommended)
• Connect negative for auxiliary system to ground