Why electric cooling engine fan not work

Engine Cooling Fan Relay 1
In the center front of the engine compartment, on the lower radiator support, near the cooling fans
Engine Cooling Fan Relay 2
In the center front of the engine compartment, on the lower radiator support, near the cooling fans
Engine Cooling Fan Relay 3
In the center front of the engine compartment, on the lower radiator support, near the cooling fans

Hose may have split . Try squeezing the hose when engine is cooled off and see if it drops out near the clamp .

you need to drive it about a week of normal driving or two days of driving as close to 50mph for 10 miles straight

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,

Hello rogelioma758: My name is Roger and I will help you. The 4.6 engine used in the 1999 Cadillac De Ville does not have freeze plugs. This was a cast aluminum engine and had no freeze plugs. How ever if you are trying to install a block heater? This engine was made to have a external heater that bolted to the block itself. Should you need further help please just ask. Please rate the answer. Thank You for using Fix Ya. Roger

Nonfunctioning engine cooling fans could result from a broken electrical connection (not hooked up, not grounded, loose ground, or a blown fuse) or a bad fan relay. It is unlikely for the motors of both fans to go bad simultaneously.

Nonfunctional interior cooling fan could result from a blown fuse or a bad climate control switch.

The normal coolant temp should be around 200-215 degrees.
The cooling fans will come on at around 225-228 degrees.

The most common overheating problem with the Northstar engine is a blocked purge line(small hose).The purge line is designed to purge air out of the cooling system.
There is a small diameter hose coming from near the top of the coolant tank (not the cap) ,this is the purge line.
With the engine idling,pull the purge line from the tank,if there is no coolant flow from this small hose,it is blocked and this will cause overheating.
If the hose is clear, check for blockage at the nipple on the tank.Or trace the hose back until you find the blockage.
The hose goes in to the engine to a crossover and comes out the other side close to the thermostat housing,the blockage may be there.

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.

Since replacing anything could cost hundreds of dollors, would you really replace it from a suggestion or would you prefer to get it diagnosed properly. It gets expensive when you just throw parts at a car. This really need to be diagnosed properly ( hands on with the proper equipment).

the coolant temp sensor is at the rear of the engine and is a "bad word" to get to. the 3 relays are at the bottom,under the fans. if you remove the driver side fan out of the way( 2 10mm bolts holding the fan) you should have good access to them. they do have locks on them and may be tricky to unplug. there is a 7/16 nut holding the relay plate down. remove and it should be easy to remove them.