temp gauge issue

[Accord07]

So im having the common temp gauge issue where it just goes to H. Literally 20 seconds after start it goes up to a little less than midpoint and then poof, all the way up.

I have changed ALL sensors ( especially the small single prong) connector/sensors. actual coolant temp is normal (tested) car drives fine, RPM stable etc.

I have heard about some sort of grounding issue. How can i wire it to a ground ? I have some extra wire laying around that i could possibly use.

Thanks !

[Fleetw00d]

Check the engine harness ground under the thermostat. Go ahead, remove it, clean up the surface and the harness end, reinstall. How is your coolant level? Make sure the radiator is full and the system is bled properly. If you raise the front of the car as much as you can on a floor jack or set of ramps, open the radiator, make sure it is full, then open the thermostat bleed fitting until you get a solid stream of coolant coming out. Close the bleeder, then make sure the radiator is full again. Install the radiator cap. Make sure you have a proper level of coolant in the overflow tank.

Did you change the sensors with used or new ones? Don't have my service manual handy to give you the proper resistance across the sensors.

It is also possible that the gauge itself is bad.

[Accord07]

re

Ill check the ground...on the harnesss under the thermo...what should i look for ?

All sensors were brand new and OEM (fan switch, the single prong x 2, one sensor by the front (near top pipe)

radiator is full and i had recently gotten the rear heater core hose replaced and repaired (i couldnt get my hand to the rear metal clamp)

this is the only nuisance i have right now. I think the gauge is not bad because it still works. But i am sure the voltage reading is off due to grounding

[Accord07]

still in the same boat. any other 3rd party ideas?

[Raf99]

Did the issue start after they replaced the heater core?

[Accord07]

Did the issue start after they replaced the heater core?

nope. was going on before too

[Raf99]

Ahh ya. So need to see if the resistance on the gauge is proper (I'll assume it is). Then the same resistance should be on the wires leading to the ECU? (would have to check manual for wiring). But .... this is probably going to be in the gauge cluster itself, seems like you tried everything else. Have an electrical manual for the car?

[Fleetw00d]

I had issues with corrosion on the printed circuit board in the cluster causing problems with the guages, including the temperature gauge. I ahve also had problems specifically with the gauges.