ardakota Posted July 11, 2017 Share Posted July 11, 2017 I have an 04 mack with the aset 460 engine and the behr fan clutch. The fan is brand new It turns off anytime the engine speeds over 1800 which i believe is what its supposed to do. It stays engaged most of the time only pulsing slow and fast and sometimes it will go off for a few seconds then come right back on kinda pulsing. I hooked up the truck to the computer and in vcads the 3 intake sensors were reading +/- 5 degrees of each other at around 110 degrees fan was still on. I could not turn the ac off in the perimeters because i havent a clue on what the password is it asks for. The high pressure switch is new as well and is closed even checked the pressure in the ac system its normal as well. The wires you couldnt read the numbers if you wanted to I dont know who was the brains who thought to put all their wiring the same exact color. Does anyone have the diagram showing where the wires going from the ac switch and fan ar located in the plug on the ecu or any ideas on what else i can do to figure this out. Oh the pulsing makes sense as when you check the soelinoid ground wire it pulses as well. One more thing can anyone help with the password? Thanks Quote Link to comment Share on other sites More sharing options...
tjc transport Posted July 15, 2017 Share Posted July 15, 2017 on my 05 granite the fan stayed on after it was sent for service. i tried new coolant sensors, fan switch, and nothing worked. sent it back to the guy that did the service and they could not find anything wrong. three months later later it started getting hot and i put the gauges on the ac. high side was 370lbs. let out a bit of refrigerant and fan worked fine for the next two years until we sold it. someone overcharged the AC while it was in for service. if high pressure is over 325 lbs i believe it is, the fan will stay on. Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment Share on other sites More sharing options...
ardakota Posted July 15, 2017 Author Share Posted July 15, 2017 7 minutes ago, tjc transport said: on my 05 granite the fan stayed on after it was sent for service. i tried new coolant sensors, fan switch, and nothing worked. sent it back to the guy that did the service and they could not find anything wrong. three months later later it started getting hot and i put the gauges on the ac. high side was 370lbs. let out a bit of refrigerant and fan worked fine for the next two years until we sold it. someone overcharged the AC while it was in for service. if high pressure is over 325 lbs i believe it is, the fan will stay on. thanks I believe i read your post so I went out and checked my pressure was like 220lbs I have even put a new switch on it. Quote Link to comment Share on other sites More sharing options...
Macktech689 Posted July 15, 2017 Share Posted July 15, 2017 The only way to remove the password is to flash and program the control module. Quote Link to comment Share on other sites More sharing options...
ardakota Posted July 15, 2017 Author Share Posted July 15, 2017 3 hours ago, Macktech689 said: The only way to remove the password is to flash and program the control module. Thanks thats what I thought. looking at the ecu log it looks like no events were saved to the ecu but the vecu had some programming in 2013 but who knows where that was. Quote Link to comment Share on other sites More sharing options...
ardakota Posted July 28, 2017 Author Share Posted July 28, 2017 Would anyone have a diagram of what wires go where to the plugs on the ecm so I Know what wires to test without tearing the whole wire harness apart? Quote Link to comment Share on other sites More sharing options...
Mackpro Posted July 31, 2017 Share Posted July 31, 2017 Behr fan clutch AC engines.pdf Quote Link to comment Share on other sites More sharing options...
ardakota Posted July 31, 2017 Author Share Posted July 31, 2017 I figured it out somehow it lost power to the high pressure switch. Quote Link to comment Share on other sites More sharing options...
ardakota Posted August 1, 2017 Author Share Posted August 1, 2017 Finally got it figured out after Mackpro helped me and I found out the high pressure ac switch had a fuse. the cover on the firewall fuse box doesnt have anything showing what fuses are what. I did a little searching and there was no fuse in it. This all started when it was taken to mack to fix the wire going to the vgt controller on the turbo. We picked it up they fixed that but told us they didnt know why the fan wouldnt shut off and sent us on our way. Quote Link to comment Share on other sites More sharing options...
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