Your cooling fan relays are controlled by the Engine Control Module (ECM). What you are unplugging is probably the Engine Coolant Temperature Sensor (ECT). The ECM will default to "fans on" if it loses the circuit to the ECT. (It loses it when you unplug it) This is why the fans come on when you unplug the connector. The engine might be overheating because the ECT may be malfunctioning and "lying" to the computer about what the actual engine temperature is. If this is the case, the ECM is not turning the fans on because it doesn't "think" it is hot enough to need them. Then again, you could have a faulty temperature gauge that is making you think the engine is overheating when it is not. (If it is boiling over, then it is OBVIOUSLY overheating and you can just disregard that last statement.)
Anyway, the only way to properly diagnose the cooling system on your vehicle is to access the live engine data and look to see what temperature the ECM is seing while you take an actual reading with an infrared thermometer or a pyrometer and compare the two. Yhe thermometer or prometer reading should be within about 5 degrees of what the ECM "thinks" the temperature is. If there is a larger error than this then the coolant temp sensor should be replaced. If the reading is within this range and the temperatur gauge reads hot when it is not, then the gauge should be replaced.
Since the fans come on when you unplug the sensor, you know that all the fan circuits are working and the ECM is capable of controlling them, so it almost has to be a computer INPUT problem, not an OUTPUT problem.
P.S. Your water pump is not an "electric water pump". The water pump is driven by the cam shaft. You should know this if you just changed your own water pump. That's what the splined shaft on the back of the pump and the splined adapter sleeve is for. The electrical plug in the water pump housing is the coolant temp sensor.
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Whatever you're unplugging that turns fans on is NOT your waterpump. Your waterpump is bolted to front of engine and is driven by fan belt. I suspect your problem is the temp sender in the side of your radiator that triggers your fans.
U may have air pocket in the system or leaking head gasket.
How do you reset the check engine light on a 1996 chevy caprice classic
SOURCE: my 1995 chevy caprice classic has a hard shifting
Not really, unless there is a shift kit in there. Have a transmission shop check it out.
SOURCE: 1995 Caprice classic keeps overheating
the radiator may be blocked, try using a good quality radiator cleaner to see if that helps, if not you might have to get it flushed out by a radiator repairer.....hope his helps......cheers.
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how do you 'unplug the water pump'?-it is mechanical and is driven by the belt at the front of the engine.
It has a electric water pump I have 2 fans on the radiator
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