shilohwestphal

Yes, I can move the fan with the ignition in the off position. I found a wiring issue which has been repaired, so now the clutch fan seems to be engaging and disengaging like it should. But I still do not hear the fan "kick in" like a box fan running. I believe the fan clutch assembly is worn out. Can these be repaired? I have priced these assemblies, very pricey. Any suggestions?

2004 Granite cv713 427 Problem is the fan clutch is not engaging. So under a load in a hard pull the temp gets high. The dash coolant temp gauge works correctly. Is there two temp sending units? if so, where are they located? So Im not real sure how to trouble shoot this. I have power going the the solenoid valve. But from what I have read, the ecm grounds the valve? So how do you check that? I also read that if the ac high pressure switch is unplugged, the fan should engage. I figured this out in the past while working on the ac. And the fan would cycle when unplugged. But now when the ac high pressure switch is unplugged, the fan does not engage. Any help would be appreciated. Thanks

if this truck doesnt already have this jumper wire harness already installed, I will order one. thanks

Good info. I will check this today. The truck had a slow coolant leak for the past couple years. This past summer we were adding roughly half gallon a day. The truck originally had the two plastic purge/overflow tanks. The radiator cap was not sealing so this was a suspect coolant leak. Both of these plastic tanks were replaced this past summer with the new aluminum single purge tank. And then in December the radiator was replaced. I suspect the motor was cleaned / sprayed off during this last repair.

Had a very similar problem with a 04 cv713 Granite 427 this week. Just loaded and was headed to the scale when the truck just died. The truck would not start, it would turn over just fine but would not fire. Noticed none of the gauges were working when I tried to start the truck. The truck also had a "no data" or "no info" displayed on the odometer. I called my local Mack dealer and talked to the main tech service man. He said the ecm is probable bad. Wasnt good news. but anyway So I started checking everything I thought might be the culprit, fuses, plugs, grounds, relays, and so forth. What I found and what got the truck running was I found moisture in the ecm connection plugs. Dried it out and plugged it back up, two plugs, and truck fired right up. All the gauges were working too. Have not yet, but Friday will put some dielectrical grease on both plugs. Hopefully we will not have this issue again.

The problem is there is not any power going to the compressor. But one reason I have found is the low pressure switch does not have power going to it either. The switch checks good. But in the contols, this switch need to be seen in the correct state before the compressor is powered. I need a wire schematic to see how things are wired. Is it direct wired? or does it run back through a module or relay or something else. And the high pressure switch is working correctly too. I does have power. And when it is in the open state, the big radiator fan comes on.

The AC has been working fine till this week. Looking over past post, this has been an issue with other trucks but I did not see any of the fixes. Pressures check fine. Checked both pressure switches, both check good. There is power going to the high pressure side. But the low pressure switch does not have power going to it. And there is no power going to the ac compressor clutch. So looks to me that is the problem. I have checked all the fuses but do not know which fuse feeds this circuit. Would anyone have any ac circuit wiring schematics for this model?

did you get your ac working? same issue with my truck no power at the low pressure switch