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SVT Shelby GT500
Radiator fan troubles and the fix
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<blockquote data-quote="SCGallo2" data-source="post: 14442576" data-attributes="member: 160791"><p><span style="font-size: 10px">I have been seeing posts and been sent private messages about inoperative radiator fans, so I figured I would share my recent experience and the fix. In preparation for larger injectors and a custom tune back in April, I scanned for DTC codes and was surprised when I saw P0481 Fan 2 (high speed fan) control circuit fault. I cleared it and went for a short drive and the code came back. So I replaced the high speed fan relay, and all was well for about a week, then the relay that I installed burned up. Since the wires to the fan checked good, I assumed the radiator fan motor was on its way out, causing an over current condition, thus burning up relays. So I replaced the radiator fan assembly with an upgraded 2013/14 unit. At this point, all was well. I got the car tuned for larger injectors and life was good… for a couple of months anyway.</span></p><p><span style="font-size: 10px"></span></p><p><span style="font-size: 10px"></span></p><p><span style="font-size: 10px">My next indication that my fans were not functioning correctly was my temperature gauge soaring towards red during some slow downtown driving. Fortunately I caught it in time, so I shut the car off before it really got hot. Letting it cool for a couple of minutes, I fired it back up with the hood raised to see if the radiator fan was running and it was not. So, I switched the A/C on full cold and blower speed to high which should activate the radiator cooling fan, but it did not turn on. After a long cool down, I limped the car back home and began diagnosing, but the low and high speed fan were now working!? So I now had an intermittent fan problem, with no DTCs. </span></p><p><span style="font-size: 10px"></span></p><p><span style="font-size: 10px"></span></p><p><span style="font-size: 10px">What I eventually discovered was the high speed fan relay had a loose connection on the 12V 40 amp supply for the fan, causing arcing inside the fuse panel. After cleaning up the contact and replacing the relay again, everything appeared to be working normally. I did some reading in the Ford Powertrain manual and found out that PCM can shut down the cooling fan motor (low and high speed) under certain conditions such as when it senses an over current and MAY NOT set a DTC. Confidence is now high that I fixed my intermittent fan problem. Now for the operational checkout…</span></p><p><span style="font-size: 10px"></span></p><p><span style="font-size: 10px"></span></p><p><span style="font-size: 10px">I created a configuration file to datalog engine temp and low speed and high speed activation points. I quickly discovered that my low speed fan was coming on at 185 degrees and the high speed fan was activating at 195 degrees. If I had a 170 degree thermostat, all would be kosher, but I have an OEM thermostat that regulates my engine temp at a 195 degree average. So at this point, the high speed fan would activate and never turn off, and that little relay gets really hot with 40 amps surging through it continuously. So with my trusty SCT X4, I set the low speed fan activation temp at 206 degrees and my high speed fan activation temp at 216. Once the low speed fan turns on at 206, it must cool the engine temp down 10 degrees (down to 196) before it will turn off. The radiator fan does not need to run at highway speeds, only when there is no air passing through the radiator. If the low speed fan cannot control the engine temp during low air flow situations, my high speed fan turns on at 216 and it will turn back off when it cools the car down by 6 degrees (down to 210), re-energizing the low speed fan to continue cooling down to 196 before it shuts off. No more cooling fan problems.</span></p><p><span style="font-size: 10px"></span></p><p><span style="font-size: 10px"></span></p><p><span style="font-size: 10px">Thanks to 54First for posting about HELMINC.COM, where I found the Ford Powertrain manual to assist in my troubleshooting. </span></p><p></p><p>[ATTACH]25759[/ATTACH]</p></blockquote><p></p>
[QUOTE="SCGallo2, post: 14442576, member: 160791"] [SIZE=2]I have been seeing posts and been sent private messages about inoperative radiator fans, so I figured I would share my recent experience and the fix. In preparation for larger injectors and a custom tune back in April, I scanned for DTC codes and was surprised when I saw P0481 Fan 2 (high speed fan) control circuit fault. I cleared it and went for a short drive and the code came back. So I replaced the high speed fan relay, and all was well for about a week, then the relay that I installed burned up. Since the wires to the fan checked good, I assumed the radiator fan motor was on its way out, causing an over current condition, thus burning up relays. So I replaced the radiator fan assembly with an upgraded 2013/14 unit. At this point, all was well. I got the car tuned for larger injectors and life was good… for a couple of months anyway.[/SIZE] [SIZE=2] [/SIZE] [SIZE=2]My next indication that my fans were not functioning correctly was my temperature gauge soaring towards red during some slow downtown driving. Fortunately I caught it in time, so I shut the car off before it really got hot. Letting it cool for a couple of minutes, I fired it back up with the hood raised to see if the radiator fan was running and it was not. So, I switched the A/C on full cold and blower speed to high which should activate the radiator cooling fan, but it did not turn on. After a long cool down, I limped the car back home and began diagnosing, but the low and high speed fan were now working!? So I now had an intermittent fan problem, with no DTCs. [/SIZE] [SIZE=2] [/SIZE] [SIZE=2]What I eventually discovered was the high speed fan relay had a loose connection on the 12V 40 amp supply for the fan, causing arcing inside the fuse panel. After cleaning up the contact and replacing the relay again, everything appeared to be working normally. I did some reading in the Ford Powertrain manual and found out that PCM can shut down the cooling fan motor (low and high speed) under certain conditions such as when it senses an over current and MAY NOT set a DTC. Confidence is now high that I fixed my intermittent fan problem. Now for the operational checkout…[/SIZE] [SIZE=2] [/SIZE] [SIZE=2]I created a configuration file to datalog engine temp and low speed and high speed activation points. I quickly discovered that my low speed fan was coming on at 185 degrees and the high speed fan was activating at 195 degrees. If I had a 170 degree thermostat, all would be kosher, but I have an OEM thermostat that regulates my engine temp at a 195 degree average. So at this point, the high speed fan would activate and never turn off, and that little relay gets really hot with 40 amps surging through it continuously. So with my trusty SCT X4, I set the low speed fan activation temp at 206 degrees and my high speed fan activation temp at 216. Once the low speed fan turns on at 206, it must cool the engine temp down 10 degrees (down to 196) before it will turn off. The radiator fan does not need to run at highway speeds, only when there is no air passing through the radiator. If the low speed fan cannot control the engine temp during low air flow situations, my high speed fan turns on at 216 and it will turn back off when it cools the car down by 6 degrees (down to 210), re-energizing the low speed fan to continue cooling down to 196 before it shuts off. No more cooling fan problems.[/SIZE] [SIZE=2] [/SIZE] [SIZE=2]Thanks to 54First for posting about HELMINC.COM, where I found the Ford Powertrain manual to assist in my troubleshooting. [/SIZE] [ATTACH]25759.vB[/ATTACH] [/QUOTE]
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