So Lately when I drive at night my engine will get really hot not over heating but hot hot.  I can turn off my head lights and just keep my parking lights on and watch the temp go down not quite sure why it would cause that but any thoughts.

Wow.  Cool one.

My first guess would be that it's purely electrical, maybe a deteriorated ground somewhere causing your temp gauge to give a bad reading when you put the extra draw on the system with the headlights.

But....do you notice the idle speed drop when you turn on the lights?

At idle it will cool down to running temp so i don't think its the gauge I have an electric fan too but my head lights don't dim when the fan turns on. couold it be and over loaded or bad bearings on the alternator?

Hmmm you sure its getting hot, I had kinda the same problem but it wasnt with my headlights.  my 87 zuk would read hot or over heating, but it wasnt overheating.. was just the temp sending unit bad.

i just installed an eletric fan and that is when it started, but during the day at like 90 degrees it stays at running temp so that is where i am stumped I can turn my lights off and watch the gauge drop.  But at idle with the lights on the gauge reads normal running temp.

Where did you pull the power from to run the fan? 

i just installed an eletric fan and that is when it started, but during the day at like 90 degrees it stays at running temp so that is where i am stumped I can turn my lights off and watch the gauge drop.  But at idle with the lights on the gauge reads normal running temp.

Okay, waitaminute.  You had to have meant "But at idle with the lights on off the gauge reads normal running temp", right?

When, exactly, does the temp appear to go up?  When you're DRIVING at night with the lights on?  Under 20mph?  Over 20mph?  When you lit it idle at night with the lights on?  During the day if you turn the lights on?

Either your engine really is heating up, or it's just the gauge giving false readings.  Either is plausible, but you're not giving us enough to go on.

If your headlights have enough draw to slow down your newly-installed fan, this would most likely result in the temp rising while you're sitting still with the lights on (idling, stopped at a light, etc.), since you may have insufficient airflow through the radiator.  If you're moving at, say 25mph, you should get good airflow through the radiator whether your fan is spinning or not.

Did you removed the mechanical fan?

With the lights on at idle and even my aux lights it will be at normal running temp.
The temp goes up when i drive at it seems any speed day or night with my lights on.
When my fan is going and i turn my head lights on it doesn't sound like it slows down at all.
The fan is hooked up to the battery pos and neg the remote wire is hooked to a ignition source. I'll try and undo the remote wire see if that has any thing to do with this crazy thing. 
Could it be too many wires close together? maybe i'll try and separate the wires a bit too.

If you have an infrared thermometer try aiming it at your radiator hose when operating normally and with the lights on and the engine revved up. Good way to see if it is the gauge or the engine is getting hotter.

check to see where your fan is hooked up to.  When you are going down the road the fan is not "on" it will only come on at slower speeds and ideal.

But that doesn't mean the fan is not turning with the wind blowing through the radiator.  At this point the fan is a generater.  Maby you a getting some weard feedback from the fan that is only complete with the lights on.

I would try disconnecting the fan and take it for a ride down the express way with the lights on and see if you still have the problem.

If you broblem goes away, find a different circuit to put it on or put a diode in the line somewhere.

UPDATE: I drove it around with headlights on and aux lights got the temp high then used the infrared gun and the exterior radiator temp 184,  the thermistat housing 179, inlet hose 164. I think it is my alternator I have heard od weird eletrical gremlins when they go sometimes time to upgrade.

Inspect and replace grounds. Battery to body, battery to engine, body to engine, engine to chassis.

-Eric

I know this will sound silly but make sure the fan is blowing air towards the engine.
I have had customers wire fans to run backwards or install a fan in front of the rad when it should have been mounted on the engine side.
Thus when driving the fan comes on and the road wind coming in stalls the fan. Drawing more current, making the engine work more to turn the alternator.

Is the fan belt tight? With the headlights on, the alternator would have a heavier load on the belt and would cause it to slip more, slowing the waterpump and the fan. Just a thought. Though it looks like the belt would be squealing if that was the case.

I had the EXACT same problem, lights on temp goes up, I put a analog water temp gauge in and the stock gauge is wrong, It stays the same temp on the new gauge whether the lights are on or off. its just some wiring issue. I think the grounds are to blame. I didnt mess with it at all since I know its just a false reading. I would try a new ground off the headlights directly to the chassis/body or battery.