Temp gauge in my 94 GMC Going crazy!!

[94 Jimmy P/U]

gauge was going hairwire when the thermostat went out (in 20* weather) i replaced the thermostat (& man its an oven in my C2500) BUT THE GAUGE WENT BACK TO WORKING FOR A COUPLE OF HOURS . I Carried a load of Recaps to Ms to a customers shop while on I-55 The gauge laid over from 195* to Past 260* & Check gauge light came on .

Stopped on the shoulder of I-55 South thought my truck overheated. IT WAS FINE . Got to the customers shop i checked it again still fine . on the way back to Memphis to the Cap Shop on I-55 North bound the temp gauge went back to working for 10 minutes then back over past 260 again . it did like this again in the last couple of days . truck runs fine w/o overheating or using water but most of the time temp gauge lays past 260* & stays there w/ check gauge light on . then sometimes it will go back to working for a few minutes . This is a 5.7L 350 GM Yall.


is it time to replace this temp gauge w/ say a pillar mount temp gauge ? (what i been wanting anyway) or do i have other problems ?



Thanks Yall

Mack

[Conlan Rose]

it might be the gauge and yes you should replace it and replace the sensor but if it continues it might be the tempture control valve my 96' tahoe has the oppisite problem it show the temp was low but the truck was always running hot.

[94 Jimmy P/U]

Thanks Conlan I Forgot to metion that i replaced the sensor also . I Had'nt thought of the tempture control valve. ill call the parts store later to see if they have 1 in stock.

Thanks

Mack (aka 94 Jimmy p/u)

[Conlan Rose]

no problem glad to help

[dipstick]

Which sensor did you replace? temp sending unit located between #1 and#8 plug... or cts on intake.
Both tied together ...cts will give a erratic gauge.

[94 Jimmy P/U]

@ dipstick: i replaced both sensors . so when i replaced both this cause the gauge to go erratic ? what can i do to solve this problem ?

Replace CTS On intake ?

Mack

[Chris Miller]

You might want to check the wire going from the temperature switch on the cylinder head to the gauge. Also, the stepper motor in the gauge itself could be bad. You could fix that with a replacement motor and soldering iron.

[94 Jimmy P/U]

Thanks Chirs Will check on those also .


Mack

[94 Jimmy P/U]

Been Kinda cool & raining on & off here the last few days & dont have access to a shop (that has room for me to pull my truck in ) weather suspossed to be better this week gonna check the wire asap & will let yall know .


Mack

[dipstick]

@ dipstick: i replaced both sensors . so when i replaced both this cause the gauge to go erratic ? what can i do to solve this problem ?

Replace CTS On intake ?

Mack

When you say you replaced both.. thought you only have one sending unit.

Yes replace cts on intake.
Probably did old post.