03 Ranger-Temp knob causes temp gauge to spike

[L2rocku2]

Hey all. A friends son baught a used 03 ranger, stock, 4 cyl, 5 spd. When the temp control knob is turned from cold to hot, the temp gauge spikes above hot !?!?! When turned back to cold, gauge reads normal. Any ideas?? Thanks!!

 

[RangerX]

Maybe a short?

 

[L2rocku2]

I was thinking that as well, RX. But what does the temp select knob and the temp gauge have in common?? I assume the temp is controlled by electric, not by a cable, so their isn't any "physical" short? I haven't seen the ranger (yet) so I haven't been able to check with a meter. Thanks RangerX

 

[robbieo11]

what does all electical components have in common?

2 things power and ground

i would beleaning toward ground in this case also pull codes see if there any temp sensor error codes
keep us updated

 

[L2rocku2]

Hey Rob. You think the temp control is grounding the temp gauge?!?

 

[L2rocku2]

Hey all. Happy New Year!! Great news on ranger. Problem was located yesterday. Air pocket in the cooling system!! Burped it like a big baby and everything is working like a champ!! Thanks for the posts Ranger & rob !!!! Much appreciated !!