FT500 SFI / FT500LITE SFI
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Auxiliary outputs
13. Auxiliary outputs
The current capacity of these outputs is 0.7A, and therefore they
can drive solenoids or relays with 25Ω of minimum resistance, the
installation of a fuse equivalent to the charge is recommended. The
auxiliary outputs have an overload protection system, with automatic
current cut-off. They trigger the charges (lamps, relays, etc.) with a
negative signal. Thus, the positive terminal must be connected to a
switched 12V.
The auxiliary outputs must be set manually according to the desired
function in the outputs (blue, gray or yellow wires) that are not being
used as injector or ignition outputs.
In case of having back current and keeping relays switched on with
ECU powered off, use a 1N4004 diode.
Each output must be configured in accordance to its function.
For more information about the outputs programming, see chapter 19.
13.1 Cooling fan 1 e 2
This output is responsible for switching an electric fan according to
the module’s settings. The relay used must be adequate to the electric
fan’s current (50A, for example). The relay is switched by negative
(sourced by the output), and the positive a switched 12V.
Important Note: the electric fan must not be connected directly to the
auxiliary output without the use of a relay; otherwise, the output will
be damaged.
13.2 Idle valve
This function opens a valve which increases the air flow in the intake,
helping the engine to idle.
We recommend normally closed valves, such as boost or purge (EVAP)
solenoids.
An appropriate relay must be used according to current and voltage.
The FT500 output switches ground and the 12V must be a switched
12V.
13.3 Air conditioning
This auxiliary output option allows for a much more intelligent control
of the vehicle’s air conditioning compressor, as the FT500 / FT500LITE
controls its activation only when the engine is already on and the
idle speed has stabilized and turns off the air conditioning when the
valve exceeds a predetermined value (a resource commonly used in
low-powered engines).
White wire
A/C signal input
A/C button on the dash
When A/C is turned
, white wire receives
ON
positive
+12V
A/C button positive when ON
White wire
A/C button input
A/C button negative when ON
A/C button on the dash
When A/C is turned
, white wire receives
ON
negative
The air conditioning will remain turned on as long as the A/C Signal
Input receives signal from the button. The signal polarity can be chosen
and it varies depending on the installation.
A/C Compressor
A/C compressor must be controlled with a relay, triggered by an
auxiliary output (sends negative when activated).
The auxiliary output that was setup as A/C will activate the A/C
compressor relay and the A/C fan. For more information on how to
setup this output, check chapter 13.
13.4 Shift Alert
This function activates an external shift light and works by sending
negative when turned on. Any of the options below can be used:
•
12V light bulb up to 5W: switched 12V directly connected to the
light bulb and the negative connected to the auxiliary output.
• Light bulb over 5W: use a relay to switch the light bulb.
• LED working as a Shift Light, which must be connected with a
serial resistance (if used in 12V, resistance from 390Ω to 1kΩ)
to the switched 12V.
•
Any “Pen” Shift Light – working in the same way as a light bulb.
13.5 Fuel pump
The fuel pump control must be done through a relay sized in accordance
to the pump’s working current. The output sends out negative to
activate the relay, which stays activated for 6 seconds and turns itself
off if the ECU does not receive any RPM signal. When the ECU reads
RPM signal, it activates the fuel pump once again.
A/C button
In order to have the air conditioning control, the A/C button on the
dashboard must be connected to a white input of FT500. The two
connection options are: