1) See the A/C IAC Kick function. Like the Terminator, HP & Dominator EFI, it's only a momentary increase in IAC.
Are you looking for a momentary increase in IAC or a high idle function? The A/C "IAC Kick" function only produces a momentary increase in IAC, so the engine RPM doesn't dip down when the A/C is turned on (or in your case, electric fans). It works fine, but it does not increase & hold the idle RPM like a high idle function. Actually, the IAC Kick function is usually not necessary. It's typically a tuning issue with the Base Fuel Table. If you need a high idle function, it can be programmed in the Sniper EFI software Advanced ICF: (1D Table, "Target Idle Speed Offset" Table Type, Switched Enable - Input #1/#2, Enabled, or Advanced Enable - A/C Kick Activation, Above) to use as a high idle function. https://forums.holley.com/showthread...8837#post88837 (Related Forum Thread)
For more information about RPM dip/instability when electric fan(s) or A/C turns on:
https://forums.holley.com/showthread...115#post242115 (Fast Idle Function For Electric Fans - Sniper EFI)
https://forums.holley.com/showthread...839#post211839 (IAC Kick For Electric Fans - Terminator/HP & Dominator EFI)
2) The Sniper EFI electric fan ground wires (pin C, light blue - Fan #1 & pin D, light green - Fan #2) trigger the relay coil − (terminal #85). Yes, terminal #85/Ground is the industry standard for good quality relays, with or without a diode. Sniper EFI instruction manual: LINK - page 17 & 50.
Electric Fan #1/#2 relay terminals (ECU ground signal scenario):
#85 - Ground signal from Sniper ECU Output.
#86 - Fused +12V power to relay coil.
#30 - Fused +12V power to relay contact.
#87 - +12V power to electric fan.
#87A - Not used in this application.
Terminals #30 & #87 can be reversed.
http://www.autoshop101.com/forms/hweb2.pdf (Understanding Relays)
Any amperage, general purpose, four terminal relay will do. However, if you want the best ECU protection, a suppression type or diode protected relay can be used. Scroll down to section 5 of this LINK for more relay information.
If your A/C compressor is ground activated, this works perfectly with the Sniper Input #1:
See page 8, "10-Pin Connector": http://documents.holley.com/199r11193.pdf (Holley Sniper EFI Quick Start Manual)
Converting A/C signal wire from +12V A/C compressor clutch wire to Sniper's negative A/C IAC Kick signal wire (Input #1) with a relay: https://forums.holley.com/showthread...699#post206699 (Sniper EFI A/C Compressor Signal Wiring Info)
Any amperage, general purpose, four terminal relay will do. However, if you want the best ECU protection, a suppression type or diode protected relay can be used. Scroll down to section 5 of this LINK for more relay information.
3) If you're using the Holley EFI A/C Shutdown feature, it requires a relay for operation. It usually triggers a preexisting A/C WOT relay.
http://forums.holley.com/showthread....9130#post49130 (Addition Information - Read Post #2 & #10)
Any amperage, general purpose, four terminal relay will do. However, if you want the best ECU protection, a suppression type or diode protected relay can be used. Scroll down to section 5 of this LINK for more relay information.
4) FYI: The A/C IAC Kick input must be used for the "Enable Fan #1 When A/C On" to function.
Page 19, "Enable Fan #1 When A/C On": http://documents.holley.com/techlibrary_199r11259.pdf (Holley Sniper EFI Help Manual - EFI Software, Tuning & Datalogging)
Then assign the A/C IAC Kick wire in the Sniper EFI software to Input #1.
See page 8, "10-Pin Connector": http://documents.holley.com/199r11193.pdf (Holley Sniper EFI Quick Start Manual)
5) Holley Terminator, HP & Dominator EFI users:
The Holley V5 EFI software/ECU firmware finally added an A/C activated option for the electric fans. Check mark A/C "IAC Kick"
in the Holley EFI software (Basic I/O - System Parameters), select a +12V or Ground Input Type in Inputs/Outputs (still in the
System ICF), and Pin Map it to an available "H" (+12V) or "G" (Ground) Input Type pin. See below for more information.
http://documents.holley.com/techlibr...teoverview.pdf (Holley EFI V5 EFI Software Update Overview - Pages 7 & 8)
https://forums.holley.com/showthread...205#post237205 (Alternative Electric Fan Control in Inputs/Outputs ICF)

Originally Posted by
Holley EFI V5 EFI Software Update Overview
Fans, Pumps, A/C
A checkbox is now available for Fan #1 & Fan #2. This ONLY appears if the A/C "IAC Kick" input is selected
& used. When the A/C IAC Kick input (an input triggered when Air Conditioning is active), the user has the
option to have one or both of the fans automatically come on, independent of engine coolant temperature.
May God's grace bless you in the Lord Jesus Christ.
'92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 200A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/3000 RPM converter, B&M Hammer shifter, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.