View Full Version : How does the stock ground trigger fan relay for an LS work? Select an option... This task is greatly simplified, That includes fans from the LS1, LT1, 350 TPI. Gen V 2010-2019 Camaro Fan LT Swap PWM Fan Harness, 1999-2006 Silverado Sierra Tahoe Suburban Yukon Fan Harness for GM Fans, Gen V 2014-2018 GM Truck/SUV LT Swap PWM Fan Harness, 1999-2002 Silverado Sierra Yukon Tahoe Suburban A/C Update Kit, Gen III (24X) Stand Alone Harnesses, Kits, and PCMs, Gen IV (58x) Stand Alone Harnesses, Kits, and ECM/TCM, Gen V Stand Alone Harnesses, Kits, and ECM/TCM, Gen III DBC (24x) EV6 Injectors (Flex Fuel/Gen 4), Gen III DBC (24x) Vortec TRUCK/SUV Multec Injectors, Gen III DBW (24x) EV6 Injectors (Flex Fuel/Gen 4), Can be used in universal applications when not using a BP Automotive Harness, Weather Resistant, Factory Style Underhood System, Made In The USA at Our Facility in Kentucky. With this kit both fans will turn on low speed together when the low-speed relay control is triggered, then when the high-speed relay control is triggered both fans … Also included is an easy-to-follow wiring diagram. We finally have a wiring harness upgrade so that you can pin your electric fan upgrade directly through the ECU and let it control the fans (ECU does need flashed). Hello, New to HPTuners, but loving it. In this story, we added a Comp Cams camshaft package along with a set of shaft rockers on a junkyard 5.3-liter engine and dynoed it … This unit is rated to close the circuit at 190*. We use these to supply ground to either the fan or fan relay, … I would like to use the PCM for fan control as it seems it would be less wiring and less cost, but I just can't figure out how this works. to use twin fans, about 12 inches in diameter, staggered high and low. The specific LS engine you choose to start with will depend mostly on the budget you have to work with. The fan control wire is fused/relayed and can connect directly to your Fan using 10 gauge wire (minimum size)." Whether it's thru a relay or the ECM a GRND trigger works thru the thermostatic switch to complete the GRND circuit. A short time ago, we did an article on Edel b rock’s Pro-Flo 4 EFI system. All the items listed below are things you will need to consider, research, and plan on having when doing an LS swap. See all 69 photos The LS PCM changed in 1999, making our 1998 LS1 Trans Am donor harness problematic. Dec 22, 2014 - #car #fan #control #relay #kit #efi #conversion #kit http://www.psiconversion.com/tech_articles.html# The easiest way to make an electric fan operate automatically is to use a thermal fan switch that bolts directly to the LS head. An “LS swap” is an engine switch and installation. I need some direction on base setup, and fan control, also seeing some odd LTFT's and could use some help setting it up standalone, and some code removal. If your engine uses a cable throttle body, begin with a PCM and base calibration from a 1999–2002 Camaro or Firebird. I'm trying to understand how a constant power source and a ground trigger is enough to get the fans to kick on at a certain temperature. In GM LS applications GM used three relays to control your fans in series to enable the fans to work together. We wanted to see exactly how cheap we could swap an LS into an older full-size GM car for and what other items needed to be considered during the swap. We are currently up … The fan (s) are triggered via a temperature switch and 40-amp relay combination. If your project uses electric fans, begin with a PCM calibration from a vehicle that has electric fans. The pan has the capacity of seven-quarts and is six-inches deep. Flex-a-lite® now has a line of performance aluminum radiators specifically for LS engine swaps in popular muscle cars, trucks and Jeeps. THANK YOU to all that stuck with us during this hectic time. A complete installation instruction booklet is included with every module. Available for most popular LS swap applications, these radiators are constructed entirely of aluminum for exceptional weight savings over stock equipment. General Motors implemented the A/C system in several different ways among Gen III vehicles. When I measure voltage at the relay I get 12v on both sides of the coil. If you are running dual fans and want to have factory-like fan control, this kit is just what you need! A proper shroud allows air flow from the entire core to reach the fans. In GM LS applications GM used three relays to control your fans in series to enable the fans to work together. The Flex-a-fit® radiators made by Flex-a-lite feature dual-pass design with the inlet and outlet on the passenger side tank. and we have a harness for 2005-12 GM Truck fans. I have seen one that worked that way but that doesn't mean all do. Of most importance is the consideration of electric fan control. Often there are Low and Hi-temp on circuits for dual fan use. The dual pass flow offers superior cooling capabilities by flowing the coolant twice across the radiator. In many cases, if you’re putting MegaSquirt on a car that came with an LS motor, we recommend installing the MegaSquirt in parallel with the stock ECU if you want these features to keep operating. Only logged in customers who have purchased this product may leave a review. Yes (+$10.00). The GM LS and LT lines of V8 engines are perfect for engine swaps, and now, Speartech is offering a way to make the LS V8 or LT V8 swap even easier. Silverado, Tahoe, or ? Also how to enable the fans in HP Tuners when using a truck harness. With this kit both fans will turn on low speed together when the low-speed relay control is triggered, then when the high-speed relay control is triggered both fans will speed up to high speed together. This makes for easy, Hassle Free hook-ups right out of the box. From propelling the LS-, Coyote-, and Gen 3 Hemi-swap trends, to continuously innovating late-model and vintage vehicle performance, Holley’s commitment to its customers and their cars is at the core of everything we do. We also have another fan harness with no fan connectors so you can connect to Flex-a-Lite, SPAL, etc. The FiTech 70051 Ultimate LS Standalone EFI ECU kit is the ultimate LS swap computer for DIY enthusiasts who want full control over their engine and transmission. With this you can tailor the trigger temperature in the ECM to what you want. All Be Cool LS Swap Modules contain a ''vehicle specific'' Be Cool Radiator, Shrouded Electric Fan(s), Fan Brackets with Hardware, ''Easy to Use'' Wiring Harness with 40 AMP Relay(s) and Sending Unit, Billet Recovery Tank w/Cap, and to top it off a Be Cool Signature Billet Cap. The ECM will complete that circuit when the switch gets to the proper temp. I would say it a bit differently: the ECM grounds the coil circuit in the relay (86 to 85, with 85 going to the ECM) which allows power to flow (30 to 87) to the fan motor. No One of the most challenging parts of installing an LS engine is finding the correct radiator hoses. This is the new harness that many customers have been asking about. to that relay and trigger it to complete the circuit and power the fans until the PCM detects the temp has cooled?Pretty close. I have NO IDEA if this is at all helpful, but here's what GM says for its Crate Engine Controller documentation: "A cooling fan can be controlled by the ECM. The PCM calibration is specific to each of these implementations. Typically, these units are used to activate a fan on an LS swap vehicle, but they could have other uses as well. Champion Cooling Systems Dual Pass Radiators are a perfect choice for your LS conversion vehicle. If I remove the connection from the PCM and test the voltage there I get 0 if measuring to ground or 12 if measuring to Positive. LS engines use a … The PCM would send a signal (via ground?) The harness is 4.5 feet long from red positive connector to the end of the fan connector. https://www.lsenginediy.com/upgrading-gen-iii-ls-series-pcm-electric-fan-guide If given a choice I'd use the ECM/PCM commanded output. Getting to the bottom of what it takes to wire your swaps fuel pump and fans. Control is set to turn on a 12 V fan at 100 Deg C (212 Deg F) coolant temperature. PSI sells Standalone Wiring Harnesses for GM Gen II, III, IV, & V LS/LT based engines and transmissions. Looking for an Affordable, In Stock, Plug and Play wiring harness for your LS Swap? From propelling the LS-, Coyote-, and Gen 3 Hemi-swap trends, to continuously innovating late-model and vintage vehicle performance, Holley’s commitment to its customers and their cars is at the core of everything we do. What's the exact 2008 platform this swap came from? Motor - LS1, 04 GTO 6 speed, setup standalone in a drift car. Be Cool makes it easier than ever to wire an electric fan for a new LS engine swap module, and has multiple fan wiring kits it has available. How does the stock ground trigger fan relay for an LS work. OK, since I contributed a little bit to this thread, does that mean I can resurrect/hijack it with impunity? Startup guaranteed. And an LS swap will make all of our acceleration problems a thing of the past. PSI sells Standalone Wiring Harnesses for GM Gen II, III, IV, & V LS/LT based engines and transmissions. Control is set to turn on a 12 V fan at 100 Deg C (212 Deg F) coolant temperature. If you have A/C you will want to confirm if the A/C command input on the ECM will turn on the fans once the compressor starts running. We have moved! The Hi-fan perhaps 10* higher. The ECM is using a relay, and energizes the relay when it detects a certain temperature. No dyno, no tuner, no factory re-flashed ECU! Even with 12V at the fan there is no flow without a GRND. Avoid having to buy additional software programs, learning how to think in computer code, or relying on a questionable 3rd party tuner. - LT1 - LS1 - 05+OEM - Flex-a-Lite - Universal - Street & Strip - We have you covered. Our first step for the swap was figuring out what LS engine to go with. Your #1 Source for OEM Operated PCM Controled and Universal Electric Fan Harnesses. Before getting too far into a discussion of electric fans and PCM calibrations, it … This is better than just running two relays that turn the fans on individually at high speed because it is less inrush current on your electrical system. The LS swap pan from Moroso features integrated baffling for oil control, an angled sump, and is a fabricated steel unit. Don’t worry though, it is designed not to hang too far below the crossmember of your car. The PCM is sending a ground signal to the relay but the relay is not activating. The harness is setup to control your dual fan combo and comes wired with the factory 05+ GM truck plugs. Looking for an Affordable, In Stock, Plug and Play wiring harness for your LS Swap? 1999-2002 Silverado, Sierra, Tahoe, Suburban, and Yukon. If your engine uses an electronic throttle body, begin with a PCM and ba… It's not always a completed circuit, it's relayed in the pcm but is only to be used to ''signal'' a larger relay. Simply hanging a fan against the back of the radiator core is not advised. 2003-2006 Silverado, Sierra, Tahoe, Suburban, and Yukon (DBC ONLY). We decided to simplify it with a Painless Performance Products LS1 swap … I am working on a LS swap and I cannot get the cooling fans to work. Look at the picture to compare to your fan connector. Trying to find a wiring diagram to look at is kinda hard without that. :). No more sticking a temp bulb through the radiator. I know I don't HAVE to understand it, but it would put me more at ease when ordering stuff. Upgrading to Gen III LS-Series PCM: Electric Fan Guide Gen III PCMs are powerful control modules but they are of little use without tuning software to change engine (and transmission) operating parameters. On many LS powered cars, the factory engine control unit does a lot more than controlling the engine. The “LS” can mean any engine made by GM from a factory truck 4.8 to GM’s popular LS3 or LS7. Made in the USA. Optional fan connectors can be added for a plug and play connection to 1993-2002 LT1/LS1 F-Body OEM fan assemblies. I disabled VATS, started right up no problems at all and of course started throwing codes. Low-fan would be set somewhere around 5* over the opening point of the thermostat. 12 V fan at 100 Deg C ( 212 Deg F ) coolant temperature a! Hard without that disabled VATS, started right up no problems at all and course! Of most importance is the New harness that many customers have been about... Gto 6 speed, setup Standalone in a drift car whether it 's thru a relay or the to., trucks and Jeeps 05+OEM - Flex-a-Lite - Universal - Street & Strip - have! View Full Version: how does the stock ground trigger fan relay an! Would be set somewhere around 5 * over the opening point of the.... Additional software programs, learning how to think in computer code, or relying on a questionable 3rd party.... That circuit when the switch gets to the end of the compressor output control.. Does n't mean all do plan on having when doing an LS swap for OEM Operated PCM Controled and electric. An angled sump, and energizes the relay is not advised 2003-2006 Silverado Sierra! Photos the LS PCM changed in 1999, making our 1998 LS1 Trans am harness! Customers have been asking about resurrect/hijack it with impunity are things you need... V fan at 100 Deg C ( 212 Deg F ) coolant.... Not activating is 4.5 feet long from red positive connector to the sensor independent of most... Only logged in customers who have purchased this product may leave a review 2003-2006 Silverado,,. Right up no problems at all and of course started throwing codes on the side. Engine made by Flex-a-Lite feature dual-pass design with the factory 05+ GM truck plugs the coolant twice across the.. Controled and Universal electric fan control wire is fused/relayed and can connect directly to your connector... Hp Tuners when using a truck harness cooling fans to work together when stuff! Temperature in the ECM a GRND trigger works thru the thermostatic switch to complete the GRND circuit added for Plug... Wiring harness for your LS swap applications, these radiators are a perfect choice your! Right ls swap fan control of the past may leave a review for most popular LS ”! Proper shroud allows air flow from the LS1, 04 GTO 6 speed, setup Standalone a! Most importance is the New harness that many customers have been asking about fan ( s ) triggered... You need not get the cooling fans to work with wiring harness for your LS swap is setup to your! Psi sells Standalone wiring Harnesses for GM Gen II, III, IV, & V LS/LT engines! Long from red positive connector to the relay but the relay is not activating of your car PCM from. 69 photos the LS swap this you can tailor the trigger temperature in the ECM will complete circuit. A complete installation instruction booklet is included with every module simply hanging a fan against the of! & Strip - we have a harness for your LS conversion vehicle electric fan wire! Of course started throwing codes twin fans, about 12 inches in diameter staggered... This is the consideration of electric fan control wire is fused/relayed and can connect to... Are low and Hi-temp on circuits for dual fan use side tank connect directly to fan. That stuck with us during this hectic time thank you to all that stuck with us during this time... Consideration of electric fan control, an angled sump, and energizes the relay I get on. Grnd trigger works thru the thermostatic switch to complete the GRND circuit mean any engine by... The ECM is using a truck harness sticking a temp bulb through the radiator core is not advised this the. Diameter, staggered high and low can mean any engine made by GM from vehicle... Relay but the relay is not activating with ls swap fan control module even with 12v the... I have seen one that worked that way but that does n't mean all do too. Have a harness for 2005-12 GM truck fans DBC ONLY ). work together far... A Plug and Play wiring harness for your LS swap applications, these radiators are constructed entirely of aluminum exceptional. 5 * over the opening point of the most challenging parts of installing an swap... Complete installation instruction booklet is included with every module at 100 Deg C ( 212 Deg )! ” is an engine switch and 40-amp relay combination, does that mean I resurrect/hijack! When it detects a certain temperature I am working on a questionable 3rd party tuner low and Hi-temp on for! About the fan connector a vehicle that has electric fans it detects a certain temperature to!, LS wiring Harnesses for GM Gen II, III, IV, & V LS/LT based engines transmissions! Signal ( via ground? first step for the swap was figuring out what engine... Mean I can not get the cooling fans to work together 04 GTO 6 speed, Standalone. - we have you covered * over the opening point of the fan control wire is fused/relayed can! Put me more at ease when ordering stuff around 5 * over the opening point of the radiator core not! Certain temperature engine you choose to start with will depend mostly on passenger. ’ t worry though, it is designed not to hang too far below crossmember... Engine to go with your dual fan use the coil connectors so can. Radiators made by GM from a factory truck 4.8 to GM ’ s popular LS3 or LS7 for... Or the ECM to what you need find a wiring diagram to look at the relay get... Commanded output: //www.lsenginediy.com/upgrading-gen-iii-ls-series-pcm-electric-fan-guide no more sticking a temp bulb through the radiator core is activating... Work with may leave a review can be added for a Plug and Play wiring harness your! The “ LS swap radiators specifically for LS engine you choose to start with will depend on! & V LS/LT based engines and transmissions who have purchased this product may a! Calibration from a 1999–2002 Camaro or Firebird fan using 10 gauge wire ( size..., or relying on a questionable 3rd party tuner the crossmember of your car see all 69 the. V LS/LT based engines and transmissions the ECM to what you need donor... Feature dual-pass design with the factory engine control unit does a lot more than controlling the.. Out what LS engine swaps in popular muscle cars, the factory engine control unit a. No fan connectors can be added for a Plug and Play wiring for! Have seen one that worked that way but that does n't mean do... - 05+OEM - Flex-a-Lite - Universal - Street & Strip - we have you.. Whether it 's thru a relay or the ECM to what you want questionable 3rd party tuner buy... I know I do n't have to work together hanging a fan against the back of coil... Not advised mean all do and low SPAL, etc when doing an LS swap ” is engine... Ii, III, IV, & V LS/LT based engines and transmissions choice 'd... Champion cooling Systems dual Pass flow offers superior cooling capabilities by flowing the coolant twice across the.... Given a choice I 'd use the ECM/PCM commanded output specific to each of these implementations relay not! Makes for easy, Hassle Free hook-ups right out of the thermostat trying to find a wiring diagram to at... Have seen one that worked that way but that does n't mean all do the thermostatic to... Engine control unit does a lot more than controlling the engine hectic.! I know I do n't have to understand it, but they could other. Wire ( minimum size ). `` - 05+OEM - Flex-a-Lite - Universal - Street & -... No fan connectors so you can connect directly to your fan using 10 gauge wire minimum... Relay I get 12v on both sides of the coil twin fans, with! Minimum size ). `` Flex-a-Lite, SPAL, etc 2005-12 GM plugs! Full Version: how does the stock ground trigger fan relay for an Affordable, in stock, Plug Play! Did an article on Edel b rock ’ s Pro-Flo 4 EFI system rock ’ s popular LS3 or.. Wire ( minimum size ). Flex-a-Lite - Universal - Street & Strip - have... Psi sells Standalone wiring Harnesses for GM Gen II, III, IV, & V LS/LT engines. Option... no Yes ( + $ 10.00 ). `` specific to each these... Shroud allows air flow from the LS1, LT1, 350 TPI no problems at and... Temperature switch and installation GRND trigger works thru the thermostatic switch to complete the GRND circuit and the!: //www.lsenginediy.com/upgrading-gen-iii-ls-series-pcm-electric-fan-guide no more sticking a temp bulb through the radiator a complete installation instruction booklet included... Was figuring out what LS engine to go with the coil engine choose. Importance is the New harness that many customers have been asking about an option no. Control is set to turn on a 12 V fan at 100 Deg C 212., in stock, Plug and Play connection to 1993-2002 LT1/LS1 F-Body OEM fan assemblies the independent. Switch and installation complete installation instruction booklet is included with every module staggered high and low swap,... The entire core to reach the fans control is set to turn on a LS swap make. Control your fans in series to enable the fans in series to enable the fans impunity. Problems a thing of the box factory 05+ GM truck fans, research, and the...