Electric radiator fan won't come on when engine gets hot

Ask to see a water pump for your car at an autoparts store like Autozone or Advance. This may be a model with a relief valve inside the waterpump. If your car is one of the rare ones with this part, it may be stuck open on your car.

Also have someone check the Electric Radiator cooling fan Relay. Sometimes it can stick to run full on when it should be off. This would be a simple fix. There are also sensors which activate the Electric Radiator cooling fan Relay. If the sensor is telling the engine to cool itself too early, then the fan would activate too soon.

You can get FREE diagrams at Autozone.com and see which Relay is in the powerbox and which is by the electric Radiator fan. Then you could simply replace the relay. But the sensor, if bad, would still tell the Relay the wrong information. It would need to be replaced, perhaps instead of the Relay.

If the car seems to be have some drivibility issues in cold weather, then the temperature sensor may be failing to tell the engine that it is cold and not hot. The sensor can be stuck on the hot settings, making the electric Radiator fan work and failing to control the engine for cold conditions.

There should be an electric fan in front of your radiator. Check to make sure that it turns on whenever the air conditioning compressor kicks on, or whenever the car is too hot. If not, the electric fan may have failed, but the most common failure point is the relay for the electric fan.
There may be a temperature sensor in the end-tank on the radiator with a three wire plug. That is supposed to turn on the electric fan when the engine gets too hot. If you short the two hot wires to the brown ground wire with the key turned on, you can test to see if the relays work for the high and low speed settings. If the contacts have burned away in the relay, you will hear it click but the fan won't turn on. The sound will help you find the relay.

Is the fan kicking on? Radiator fan! When engine gets hot, radiator fan should kick on under the hood.
If it does, then there is a blockage in the radiator preventing it from circulating the coolant to dump the heat. Get a Rad flush.

If the fan does not kick on, then check the fan fuse and relays, usually found in an electrical distribution box under the hood. Consult your owners manual for its location and specific fuses / relays.
Possible bad fan too.. but disconnect the fan at the plug in the wiring, and test supply wire for voltage, when engine is above normal temperture.

It is located under the hood between the radiator and the front grill. You will have to remove the platic cover between the radiator and grill to see it.

So youre saying the fans are coming on and going off like they should, have you changed your thermostat and be sure to burp the system getting out all the air bubbles. And the check engine light will not always go out on its own, most times manually clearing it or disconnecting the battery is the only to go if you dont have a generic scan tool

have you had the coolant changed lately? there may be an air pocket in the cooling system which can lead to a blown head gasket.

All you have is one or two fans? Have you checked or replaced the thermostat? The thermostat opens when the engine gets to operating temp, and allows the water in the radiator to flow through engine and the water pump pumps the water out of the engine back through the radiator to cool before it goes back through again. I check the lower radiator hose to see if it get hot like the top hose or you could take the lower hose of the pump to see if it is pumping. I would start with a radiator flush and do this a couple times, prestone makes a flush and Im sure someone else does. do that then change your thermostat, make sure when you put the new one in it goes in spring side down..

There is a fan relay in the fuse box in the engine compartment. Usually that is the reason why it won't turn off. It fuses in the on position. If you have the manual it will say which one is the fan relay. just pull it out and get a new one. They are not expensive.

Hope this helps

By pass it. remove wires from fan leaving enough wire to splice onto.Run 2 wires 1 to ground and 1 to a power source in fuse panel that only has power when ignition is on such as running lights . this by passes fuses and relays and assures your fan is running if your vehicle is running.

This could be a multitude of things:

Stuck closed thermostat.

Cooling fan not coming on.

Clogged radiator.

Low on coolant.

Water pump failing/leaking.

Head gasket blown, leaking exhaust into antifreeze.

Clogged catalytic converter.

Thermostat: If the Van heats up, then feel the upper radiator hose. If it's cold, then your thermostat is closed. Replace thermostat.

Coolant: If low, simply fill with distilled water and coolant. Low levels will let engine over heat.

Radiator: If there are cold-to-the-touch spots on the radiator after it should be warmed up, then a clogged is probably occuring. Have radiator flushed.

Head Gasket: If you smell exhaust fumes in your coolant reservois tank, then you got a blown head gasket.

Cat Converter: Only can be tested if off the car. Or you could try a non-contact thermometer. These are also good to testing cold spot on radiator or if thermostats are open.

Cooling fan: If mechanical it'll be spinning. If electrical, it should come on automatically with the A/C, or when it gets hot.

Water pump: Will be leaking from the front if it needs replaced. On a van, it's a tough job.

Good luck!