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mcratchet1

need help with 4-2 blink code please

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I have 2006 Mack mr688s (032711) with blink code 4-2, im assuming it has something to do with fan clutch because its staying engaged. I just put a new clutch on about a month ago, anybody have a schematic or advise?  Thanks!!

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You should have a constant 12v at one wire of the fan solenoid, the other wire is a ground signal from the ecu to disengage the fan. It could be as simple as a blown fuse (don't quote me but #41 I think?) Or could be a break in either the hot wire or ground. 

I've seen many that were broken wires, rather than chase the mess around and on top of the transmission, I just rewired, bypassing part of the harness.

I don't have a schematic with me right now, but can give you pin numbers Monday if you still need them.

 

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ok thanks did you run a new wire straight from ecu if so i could use the pin# for the ground if you have it Thanks Again!!

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Yes, if you aren't getting the ground from ecu, I ran a new wire from eco to fan solenoid. My daughter was sick this morning so I stayed home today, but I'll get the info in the morning.

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Pin number 9 at ecu connector j1(the top one) is your ground signal to turn fan off. Before you start splicing, check that wire for continuity to the fan solenoid. 

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