2003 Civic Temperature indicator drops to zero during driving

[hussmy]

Hi all,

Since last few weeks a strange problem has developed in my Civic 2003. The temp indicator suddenly drops to zero (seems no power to indicator). I have tried to establish reason or events which may cause this but no success. the indicator drops at any time like after driving around of 30 mins or sometimes in cold engine. Sometimes once it drops never comes back to normal and sometimes it drops and after few minutes come back to normal.

Any suggestion or any help what may be the cause and how to rectify?

 

[AlaskaB16]

Perhaps your thermostat is stuck open thus preventing your engine temps from getting to normal ops. While driving and your temp drops, do you still have full heat? If not, it's your thermostat for sure.

 

[hussmy]

Thanks for input Alaska. I had in mind about thermostat but the temp indicator doesn't drop temp gradually and come back to normal. It goes straight to zero (like no power coming in indicator) and when it goes up, comes back to normal.

Through forum and online search i would like to check temp gauge sending unit (a single wire sensor which gives signal to temp indicator) but cannot locate on my engine. There may be possibility that the wire is broken somewhere.

 

[AlaskaB16]

Temp gauge wire (ECT sending unit):

EDIT.. Can't find specific photo to 03 civ, but it should be the same as the rest. A single wire under the distributor.

Again though, drive around till your temps fall. Do you have full hot heat? If yes, thermostat is more than likely good. Temps should drop slow. If it drops like a rock then you probably do have a loose temp sending wire.

 

[hussmy]

That would be great if i can find temp gauge wire.

Thanks

 

[AlaskaB16]

I just did a quick google but couldn't find 03 specific. You may have more time to do so. Easy to find though.

 

[hussmy]

I have spent good time on google to find but no success. I will try to post pic of my engine, this will help you to identify ?

Thanks

 

[hussmy]

Thanks Alaska for input. This has been solved and the culprit was old battery and deposits on "positive" terminal. I dont know how it links with temperature indicator but when terminal was cleaned with old battery i saw 80% result (i.e occasionally it was happening) and now i have changed battery so it is completely gone.