T800 fan running

Wanted to post an update. I was able to locate the wiring layout that I needed via KW eportal. My wire colors were entirely different, but I located where they said the high pressure switch is. The switch that was previously replaced is attached to the high pressure side near the dryer/accumulator, the wiring layout listed the switch as "front right top of engine". So I went to the plug that was located there.

It is ran in a wire loom with the wiring for the ac compressor and for the coolant res sensor. Goes across the front of the engine and runs down the driver side and then down to the ecm. I tore apart the whole loom and traced the wire. I had a green wire and a grey wire. The green wire I traced all the way back to the ecm and did a continuity test, it checked out. The gray wire didn't go directly back to the ecm, it went to the plug on the power steering reservoir and then to the ecm. No continuity on that side. I pulled the loom for the power steering res and found....a broken wire. I was confused as to why the wire ran through the power steering res sensor...and still am. But, I repaired the wire, zip tied everything out of the way and starter the truck with all of my switches and sensors plugged back in. Truck built up to 100psi and the fan shut off as intended. I let the truck run until it has topped its air, then I hit the fan switch to cut it on, it came on immediately. I ran it for a minute or so and then shut it back off. It shut off after exactly 30 seconds (programmed time). I did this a few times and it worked great.

I also replaced a nox sensor that was unrelated to the fan so I was doing a regen with insite using the analyzer setting but the regen failed because the truck would not get hotter than 182 degrees still. Its been cold here and that may be the reason. I am going to put a blanket across the grill and try again to get it up to temperature and then try a regen again.

Thanks so much for the help!!

 

Does the truck have an air to oil power steering cooler? If it does could be the reason for it being connected to the power steering system.

 

It does have a steering cooler. I found the sensor is just a low fluid sensor. Now I think my thermostat is bad because I can't get above 180 stationary which is causing me to not be able to do a regen. I get a warning from insite after it "trys" to do one, it then says that the coolant temp is too low and exhaust failed to reach temperature.

 

They can have power steering temp switches that kick the fan on when the p/s temp is too high.

 

You are correct. I found an "options" wiring diagram that included a power steering temp switch. It showed it wired in line with the a/c switch. When that wire was broken, the ecm reads it as the a/c switch is what is kicking on the fan. She's all fixed up now. Finally got it to run a regen after getting her warmed up and everything came back great. Drive is happy to be back in his truck. Now I have to do a set of injectors in a different truck...it never ends.

Thanks for the help!!