Ok, I have been having this problem with my temp gauge in my cluster. The car is a 99 civic with a gsr swap. Lately when I have been driving, the temp gauge will start to creep up past normal. When I come to an idle, it will either go back to normal or keep going up. Also, when I turn my parking lights/headlights on, the temp needle jumps like another 1/4 way up, and if I turn my lights off it will jump right back down to where it was.

The engine bay feels like it is hotter than it used to be (last year with different swap), the fan kicks on. Not losing or leaking any coolant. What would cause my temp gauge needle to jump with the lights getting turned on, and go up and down at random when im driving. Also sometimes the needle jumps with the bass from the stereo.

 

Check the dash harness grounds.
When one circuit, [park lights] effects another, [temp. gauge] it is almost always because of grounding issues. 94

 

Dash harness grounds? Where would I find those?

 

Now that I think about it, behind the cd player on the metal dash frame there was a black wire (ground maybe) attatched to the frame. I did ground a few gauges to that same spot. Do you think that could be the reason? I noticed this only happens when I turn my stereo up high. As soon as I shut my car off, and turn it back on it goes back to normal.

 

Yes that is the ground. use some grounding washers there and clean up the dround while you are there.

 

I went driving for an hour without my stereo/sub on and everything was perfect, even with turning the lights on/off, everything worked properly. But as soon as I turn my stereo/sub on, is when this starts happening. The temp gauge starts going up, than down, and when I turn the lights on/off it makes the needle jump.

What would cause my stereo to do this to the temp gauge?

 

Grounding. 94

 

Yes I still havent done that. I am going to take out my cd player and take the ground wires off that I put to the same spot as the original one, and just leave the original one there by itself and hope that will fix the problem. Think that is why? I mean adding 2 more ground wires to it would cause this problem? Will go try that now and post the results tonight.

 

Well the ground spot i had it grounded to, took everything off and still the same problem. I noticed that ground went from the car harness to the radio adapter plug. But back together normal it still does the same thing.

Yesterday night was quite cool, it is like 20 degrees hotter today atleast, now that i notice, it kind of seems like its happening when its really hot out. Yet still fluctuates with the lights, and at random it jumps and drops even with the radio off and those ground wires not conected.

There have been times when the bass was so loud the temp gauge needle would bounce with the bass when it hits, could this have messed up the temp needle at all?