Problem with temp gauge

[SouthTexasDiesel]

Got the drive my new deuce around yesterday and saw that the temp gauge was maxed out when I was just leaving the truck at idle. I turned off the Acc. switch for a second then back on and the gauge read normal 150*. After idling for another few minutes it maxed itself out again. The engine temp was fine the entire time.

Any ideas on what could be causing this?

 

[MoAllen]

Hi Might be a bad sending unit. Did you do the normal things to check, Belts, top the fluids off. I will check the 20 manual or trouble shoots manual if you dont solve it .
Allen

 

[cranetruck]

More info.

 

[dk8019]

My oil gauges does the same thing, normally it will read 60PSI at speed, around 30 at idle, but ever so often it drops off the chart for no reason, flipping the power switch off and back on brings it back to where it should be. I'm guessing it's a lousy contact somewhere, I need to hunt it down.

 

[rattlecan6104]

I have a similar issue as the op, except it wont even show the actual temp, sits at 120 for about 30 seconds, then snaps over and maxes out.

 

[kastein]

maxed out temp usually means a short to ground somewhere on circuit 33, try unplugging the sender, if the gauge drops to below 120 you found your problem. If it doesn't try unplugging circuit 33 from the back of the temp gauge, if it drops below 120 you have a short from circuit 33 to ground somewhere between those two connectors. If it does not drop, your temp gauge is probably at fault.