Temperature Needle Going Through "H" and Over

[Donut Limo]

if your scanner shows 198-207f ECT thats perfect.

the sending unit is a separate circuit. im thinking the gauge is damaged or the wire is shorting on something. when that wire grounds itself, the gauge will peg so any kind of rubbing or chaffing with that wire exposed will make the needle jump up.

you can measure the resistance from the sending unit to ground and again from the wire at the gauge to ground and might be able to find the problem or at least isolate it to the gauge. did that make sense?

 

[fmanalopr]

What kind of reading should I expect when testing the cluster? or should I get the same readings from the sending unit?

 

[poff1986]

Have you checked the wires going to the guage cluster? Maybe when you changed the led's the connector was not fully connected? Also have you checked the terminal on the Connector for the ECT? See if it is corroded making a bad contact. The default for when there is a wiring issue, is that the temp guage will go all the way up, Thats why I am assuming there is a wiring issue, If you have replaced all that stuff, im sure your coolant is full, so there is really no need to replace the head gasket, if your thinking the head gasket is leaking, connect a coolant pressure tester where the radiator cap is, pump it up to 5PSI and start the engine, if the guage goes up after approx 5MIN of running time, you have a head gasket problem. Good Luck! (Mostly what donut said...)

 

[Donut Limo]

What kind of reading should I expect when testing the cluster? or should I get the same readings from the sending unit?

i can't find a test for the gauge itself. what i meant was the resistance at the sending unit and at the gauge where the yel/grn wire goes into it should be the same. if the resistance is a lot less entering the gauge it would mean there is a short. this would definitely be tricky to find if it only shorts while driving. my guess is as long as the car is running normally, the fluid levels aren't changing, and you have a healthy ECT sensor, it's only an indicating error and you won't be doing any damage driving the car while you're troubleshooting

 

[99F23VTech]

Okay i am having a similar issue as a matter of fact. But i messed with mine, i bought gauges off line and installed them i ended up removing the needles from the cluster and yeah ever since i havedone that my needle sits at hot... So if you have had any kind of work on your cluster i would either buy one off ebay or go to a junk yard and pick one up and install it to see what it reads, i mean if you would have done this from the beginning you probably would of saved a ton of money...

 

[fmanalopr]

Well for now my car is "normal" but I had to leave my fans always on cause when I tested them my temp whent all the way to 210 & still no fans. I checked the fuse and replaced the sensor that sits were the thermostat ( no thermostat also ) goes and no go.....if I missed something to check please let me know but at least no more overheating.......for now!!!! By the way I took the radiator back to check it and voala!!!!