Electric cooling fan will not turn off on a 1999 jeep cherokee

What's the issue/problem with cooling fan?

The main cooling fan on this 1999 jeep cherokee, the main fan all depends.

These jeeps come with diffrent fan set ups. Here are a few, the first may be a fan driven off the motor by a fan belt and a another fan which is electric. the primary fan used for cooling is the fan that runs off the engine with a belt. the other electric fan is more the air conditioning system, this fan is used for cooling the condensor mainly. the engine driven fan is for the cooling system.


Another system fan set-up on these jeeps would be the motor driven fan by belt with another electric fan in front off it, the diffrence between the first and this one is that the first fan system is side by side and this one is set-up one in front of the other but the concept is the same, the fan driven by the engine is mainly for the cooling of the engine coolant and the electric fan is for air conditioning cooling.

In both set-ups the electric fans also help the cooling system but are mainly used for the help in cooling when the a/c is turnned on, the a/c condensor builds up heat the same as the radiator does, one fan is unable to cool both the radiator and the condensor, this is why some cars have two fans.

Good day, hope this is helpful,

Yes, it's called the thermal fan switch.

Sounds like your cooling fan relay is bad the jeep grand cherokees are known for this, first thing i would do is unplug the radiator cooling fan and run 2 jumper wires direct from the battery to the fan connector if the fan kicks on your fan motor is good and the relay is bad, if the fan doesnt kick on replace the fan motor with a new unit, the cooling fan relay on your particular model jeep is located under the passenger headlight and requires you remove the front bumper to replace it, however some people cut a small hole under the headlight to access the relay the faster way but if your not to keen on cutting holes in your car remove the bumper and replace the relay if the fan checks out and you wont be overheating anymore...

It is possible that there is a bad temperature sensor. Have it put on a diagnostic machine and possibly reset all codes.

have you checked that the rad is clear and air can flow through it freely,,,is it blocked up so the water cant flow through it freely ,is the fan realy working or sezed up so it cant turn round??
if all this is ok, they changing the temp censor or for a test run,,,short the fan temp censor plug out with a bit of whire this should start the fan up,,,(watch your fingers when doint this) go for a run to see if the motor stayes cool

the relay is maybe sticking.
or there is a call for cooling when the engine is off.

if the fan turns off after a min or two then its ok.

if the fan stays on and will not trun off ever even after 30 mins then the relay is staying on and needs to be taken out and replaced.

check fuse and relay.if all is good.hot wire cooling fan using jumper wires to battery.if fan dont run replace the fan.if fan does run you have a open wire or bad connection at cooling fan electrical connector.

The radiator cooling fan used on the 4.0L engine is
an hybrid fan design. The hybrid fan system consist
of a low speed viscous driven mechanical fan and a
electrical fan.
The hydraulic fan used on vehicles equipped the 4.7L engine, replaces both the electric fan and the engine driven mechanical fan. The hydraulic cooling fan is integral to the fan shroud and is located between the radiator and the engine. The power steering pump supplies the hydraulic fluid and pressure to rotate the cooling fan blade, while the electrical part of the fan is controlled by the JTEC. The hydraulic fan drive (motor) consists of the three major components:
- Steering flow control valve
- Fan control valve
- Two stage G-rotor hydraulic drive
The hydraulic fan and drive is not serviceable.
Therefore any failure of the fan blade, hydraulic fan
drive or fan shroud requires replacement of the fan
module because the fan blade and hydraulic fan drive
are matched and balanced as a system and servicing
either separately would disrupt this balance.

relay sounds stuck...call a parts store for pricing