Bad temperature gauge or sensor?

[Meanwhile]

One of the gauges I pay a lot of attention to is the temp gauge. About a week ago I heard my fan come on, I looked at the gauge and it read about 185 degrees. It struck me as odd so I started paying more attention to when the fan come on. Now the fan comes on more frequently when the gauge is around 180-185 degrees but it also comes on between 200-205 like usual. My first thoughts are pointing me to something gauge related. Have any of you experienced anything similar?

Another odd thing about this truck, I could’ve swore it idled at 650 rpms but now it’s idles at 700.

[Rawze]

maybe the A/C kicking it on?

[Meanwhile]

I guess I should add, this is a CM2250 with about 417,000 miles on it in a 2013 Kenworth T-660

[Meanwhile]

My AC hasn’t worked in months. I even made sure all of the AC stuff was off

[Lonestar10]

Just because AC doesn't work doesn't mean that the high pressure sensor isn't bad and tripping the fan on.

Things that can turn fan on

Ecm losing power whole engine would cut out and in

Faulty fan air solenoid

High intake temperatures

Water temp 215ish

Some trucks very high oil temps 240+

AC high pressure switch

Faulty fan override switch

I'm sure there might be more but best I can do off the cuff.

[Meanwhile]

Thanks! I’m guessing I could unplug the AC high pressure sensor and see if that changes anything?

[Chamberpains]

Or you pull out your laptop and inline adapter and monitor the switches and sensors Lonestar mentioned and see exactly what is going on.

If you don't have Cummins Insite, then this would be your 1st step in getting this figured out.

[Lostfarmboy]

On mine after changing the high pressure switch several times I repinned the plug and have had no more problems. Just something else to think of

[Meanwhile]

I don’t have Insite yet, it’s on it’s way though. I’ve unplugged the high pressure sensor and I’ll see what it does today and update. Thank you all for the information!