2016 Freighliner Cascadia Cummins IsX fan on

Here is the fun stuff.
Replaced fan solenoid, solenoid connector, fan stays on. Same with the high pressure switch yet no AC in the system.

Fan Goes off when truck turned off.

more fun stuff, coolant temp sensor broke, by the thermostat housing , yet temp gauge works fine. Can’t explain that one. I think I found the sensor for the gauge.

smaller one by the pipe is for the gauge, that’s my guess, since the gauge still works

the coolant temp sensor is the one that’s now a two piece. Going to try and swap out the coolant temp sensor and see if that fixes my fan being constantly on. Then I get to do a fan over ride switch if all goes well.

 

Little bit of an update. The sensor that broke is for the EGR. The coolant temp sensor is just the small two pin one. Two pin one Ohmed at .3 ohms.

now to the weird part, new high pressure switch on, connected. No change of fan operation.

low side wire was broken at the connector for the harness side connector going to the low pressure switch. Cut the other one and tied them together. Started the truck and fan works like it should. Take them off and fan switches on. Touch them together nothing changes but when truck turned off and back on fan operates like it should.

here I thought the low pressure switch only controls the AC compressor. Which to my automotive understanding it should.

anyone else may have some guidance?