Holley 550-407, Installation Manual, Page: 19 / 54

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14.0 ADDITIONAL OUTPUTS
There are 3 optional outputs available on the system that can be used for the following features:

Air Conditioning Shutdown at wide open throttle

Electric Fan #1 output

Electric Fan #2 output
There outputs are located in the “Input/Output” connector. This is a 3 Pin connector is located about 52 inches from the ECU. A mating
harness is included with the system.
The following indicates proper wiring for these features.
A/C Shutdown
–
This output will provide a +12 volt output a defined throttle position. This output can be used to trigger a relay that
deactivates the A/C at higher throttle positions. This may require the installation of a 5 pole relay in the existing A/C wiring. This wire is
located in pin A of the 3 pin Input/Output connector and is Gray with a Yellow stripe.
Electric Fan #1 output
–
This output will provide a ground output to trigger a relay used for a cooling fan. This output should never be
directly connected to a fan, but the relay that powers the fan. It should be connected to the ground trigger of the relay. This wire is
located in pin B of the 3 pin Input/Output connector and is Gray with a Black stripe.
Electric Fan #2 output
–
This output will provide a ground output to trigger a relay used for a cooling fan. This output should never be
directly connected to a fan, but the relay that powers the fan. It should be connected to the ground trigger of the relay. This wire is
located in pin C of the 3 pin Input/Output connector and is Gray with a Green stripe.
Figure 26
14.1 Transmission Wiring
The transmission harness can be used on 4L60E, 4L65E, 4L70E, 4L80E, and 4L85E transmissions. Each connector should be labeled.
Transmission ECU Connector (P4)
–
Plugs into the ECU. Plugs into the last connector opposite the main harness.
Main Transmission Connector
– Simply plugs into the connector on the transmission. Located on the driver’s side of a 4L80E (installed
horizontally) and the passenger side on a 4L60E (installed vertically).
Vehicle Speed Sensor (VSS)/Transmission Output Speed Sensor (OSS)
– Located on the rear drivers side on a 4L80E and the rear
passengers side on a 4L60E
Turbine Speed Sensor
– The 4L60E does not have a turbine speed sensor. It is located towards the front driver’s side on a 4L80E. Note
that a 4L70E has one internally wired, but is not connected to the Holley harness. The turbine speed sensor is not used for any
calculations in the ECU, just for monitoring purposes.
Brake Switch (Grey)
– Wired to the brake light switch. This must be installed to a +12v source (as most brake light switches are). This
input is used to unlock the torque converter when the brakes are applied.
Ground (Black)
– Connect to a good chassis/engine ground source
Power (Red)
– Supplies power to the transmission solenoids. This should be connected to a +12v switched power source (must be
capable of supplying 5 amps).
NOTE: The power supplying this wire must NOT be tied to the same point that the ECU switched power wire (red/white wire) is
connected to. If they are tied together, the transmission power could back-feed power to the ECU and the ECU/engine will not
shut off when the key is turned off. Use a relay or separate switched ignition power pickup point to supply power to the
transmission harness.