Kevin Twombly Posted June 23, 2023 Share Posted June 23, 2023 I have a 06 ct 713 with an ami 370. The truck is new to me a few months ago and after getting it back to almost new The fan has decided to be engaged in a hunting mode, sounds like it is going to full engage and then releasing, I brought it to the dealer and could not pinpoint it, the fan has 5 wires going to it , no air lines, I saw a wiring diagram in a post but it did not look like my engine my ac works fine and engine runs at 165 deg If anyone has a manual or info I would greatly appreciate it I tried buying a manual from Mack with no luck Quote Link to comment https://www.bigmacktrucks.com/topic/72970-clutch-fan-surging/ Share on other sites More sharing options...
Joey Mack Posted June 23, 2023 Share Posted June 23, 2023 you have what is called a ''Smart Fan'' it will ramp up and down based on signals from the EECU.. Next time you are at the Dealership, have them show you the Smart fan setting.. It is on PTT. It can be shut off and on.. Quote Link to comment https://www.bigmacktrucks.com/topic/72970-clutch-fan-surging/#findComment-533458 Share on other sites More sharing options...
Mackpro Posted June 23, 2023 Share Posted June 23, 2023 Here’s the bulletin for the same fan clutch but on the Aset AC engine that’s in the CX and CH style trucks. Your AI engine has 2 connectors on the engine Ecm while the AC engine has 3 connectors on the engine Ecm. Troubleshooting should be code to the same . I’ll try to find the one for the AI engines https://pdf4pro.com/cdn/service-bulletin-mckenzie-tank-lines-a3dd0.pdf Quote Link to comment https://www.bigmacktrucks.com/topic/72970-clutch-fan-surging/#findComment-533503 Share on other sites More sharing options...
Kevin Twombly Posted June 25, 2023 Author Share Posted June 25, 2023 Thank you so much that great info Now I just need time to figure it all out!! Thanks again Quote Link to comment https://www.bigmacktrucks.com/topic/72970-clutch-fan-surging/#findComment-533581 Share on other sites More sharing options...
Mackpro Posted June 26, 2023 Share Posted June 26, 2023 It seems they never made a troubleshooting guide for that style fan clutch on the AI engines. The electric viscous fan clutches for the AI and AC engines look identical and will actually bolt up but they have different part numbers. The troubleshooting should be the same only difference would be engine ecm pin location. Quote Link to comment https://www.bigmacktrucks.com/topic/72970-clutch-fan-surging/#findComment-533591 Share on other sites More sharing options...
Kevin Twombly Posted August 27, 2023 Author Share Posted August 27, 2023 So I finally figured out the fan problem! Even though I had the ac system checked and charged. As well as had it turned off, the high pressure switch by the dryer, the green one with the pig tail , was staying open , gave no codes and caused the fan to engage and disengage constantly above 1200 rpm 2 Quote Link to comment https://www.bigmacktrucks.com/topic/72970-clutch-fan-surging/#findComment-537768 Share on other sites More sharing options...
Joey Mack Posted August 27, 2023 Share Posted August 27, 2023 Good deal!! thanks for posting the fix.. easy repair, and you didnt need to fire the parts cannon at it.. Quote Link to comment https://www.bigmacktrucks.com/topic/72970-clutch-fan-surging/#findComment-537769 Share on other sites More sharing options...
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