Temp gauge keeps bouncing around making the fan stay on

My truck is doing this now too. Did the harness fix work?

 

Wondering if changing this harness ended up fixing the problem.

I have a 2006 Detroit 60 freightliner
My truck has an issue very similar to this. As your driving down the road the coolant gauge will drop to Zero and the fan kicks on and then the engine light. No shutdowns but the problem can last up to 10 minutes.

 

I forgot how I got mine fixed, I think I had a loose connection at the fuse panel.

 

I am having the same problems but i believe its my ecm. How do i get the voltage back up to make sure i can get 50 miles

 

This is years later lol but my trucks currently doing the exact same thing been 2 weeks now can’t find a bad ground anywhere reading 46 code on a ddec 3 in a 1995 FLD freightliner was curious to see if you can help me out I’ve seen reply’s on a lot of older questions I haven’t changed out the water temp sensor ?

 

I hate when ######## ask questions and never come back and tell what the fix was.
Mine is doing the same thing on a 2000 fld 120 with a 1999detroit series 60.
I replaced the passenger side sensor so far and hasn't solved the problem.
Tomorrow I will do electric line work and when I figured it out. I will come back and let you guys know what worked for me.

 

http://ww2.justanswer.com/uploads/gowest/2010-12-13_032343_edm.pdf