# Radiator fans don't come on and temp gauge doesn't work



## cecygaby (Jan 30, 2012)

I have a 1996 200sx with the ga16de that has 2 problems: 

1) the fans don't come on by themselves when i get it to normal operating temperature and beyond, to almost 190 degrees, unless you unplug the electrical connection to the temp switch at the intake manifold, which makes them run all the time, a new temperature switch is currently installed

2) the temperature gauge does not work, fuses check good and also swapped relays 

checked temperatures at block, head and radiator to get an average and come with my numbers, not very familiar with nissan and this is my first one, want to fix these details before it becomes my daily driver, any help will be appreciated, thanks.


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## smj999smj (Jan 1, 2006)

Most Nissans won't kick on the fans until approx. 200-210 degrees F. The fact that you unplugged the ECT sensor and the fans came "on" eliminates most of the possible problems except for a bad ECT sensor or a bad ECM (doubtful). There's a good chance you just haven't got the engine hot enough to cause the ECM to run the fans, or, you have a bad ECT sensor. Since you just replaced the ECT, I would doubt that's an issue. The best way to check or diagnose this would be with a scantool to see the temperature input to the ECM.

As far as the temperature gauge: The coolant gauge sender is a single contact switch that grounds through the switch to the engine. Disconnect the temp sender and, with the key "on," you should have 12v at the harness connector. If you run a direct ground to the harness connector w/ the key "on," the gauge needle should rise to the top of the "hot" range (you should apply direct ground no more than 10 secs). If you have power and grounding the connector causes the gauge needle to rise to the top, the coolant sender is faulty. If you have no power at the harness connector for the sender, you'll have to check the continuity of the wire from the coolant sender harness connector to the combination meter. If the wire is good, then you'll need to check for power to the combination meter. I would suggest you get some wiring and connector diagrams at this point. If you have power to the combination meter, then either the printed circuit has an "open" or, more likely, the coolant gauge is bad.


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## cecygaby (Jan 30, 2012)

Ok will try running the motor to 200-220 tomorrow, now for the temperature sending unit where is this one located at, I looked all over the engine an cannot find it, read it was underneath the distributor but there is nothing there, thanks in advance


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## smj999smj (Jan 1, 2006)

As I remember, it was below the distributor. Maybe that why it's not working...cause it's not there? Part number is 25080-89903. If you do a Google image search for "Nissan 25080-89903," you'll see what it looks like. Should be a yellow/green wire going to it. The connector is small, black and rectangular and should have a rubber cover on it.


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## cecygaby (Jan 30, 2012)

everything is working now the way it should, thanks guys for all the input you Rock!


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