[tray money]

I have a 2000 Grand Cherokee, it's a 4wd, 6cyl and my cooling fan has stop working, I replaced the old fuse with a new fuse and the fan still won't come so now what.

[RickMN]

Most likely a fan relay issue.

Read this post and download the wiring diagram to see how it works. Not exactly for your car, but close enough to get how it works.

Radiator fan won't turn on

[TxGreaseMonkey]

Radiator Fan Doesn't Run

Radiator fan failure is one of the leading causes of engines overheating, often resulting in warped aluminum heads, blown head gaskets, and damaged valves.

1. Check all under hood and under dash fuses with a test light or multimeter:

a. Multimeter. Set multimeter to DCV, turn ignition switch to ON (Position II), touch the black test lead to ground, and touch the red test lead, in turn, to each test point on the fuse. The meter should record 12+ volts. Voltage must be recorded at each test point on a fuse; otherwise, the fuse is bad.

An alternative method, which is very fast, is to set your multimeter to audible ohms, DISCONNECT THE NEGATIVE BATTERY TERMINAL (or you could blow the fuse in the multimeter), and touch the red and black test leads to the test points on each fuse. When you hear the meter buzz, you know the fuse is good. If your meter doesn't have audible ohms, but it does have ohms, you can still use this method--just read the meter instead. The alternative methods perform a continuity test on the fuse. Just remember to de-energize the circuits, by disconnecting the negative battery terminal, and record any radio activation codes first.

b. Test Light. Turn ignition switch to ON (Position II), connect alligator clip to vehicle ground, and touch the probe to each test point on the fuse. The test light must come on at each test point on a fuse; otherwise, the fuse is bad.

These methods allow you to accurately and quickly check all under hood and under dash fuses in several minutes, even in dark, cramped locations. They eliminate the possibility of removing and replacing the fuse in the wrong slot. Should a fuse test bad, use the fuse puller, provided in the under dash fuse/relay box, to remove it.

The radiator fan fuse is usually located in the under hood fuse/relay box.

2. Jump the radiator fan motor and ensure it runs. Disconnect the radiator fan motor connector and attach jump leads to the battery. Better yet, use a Power Probe II--it's safer, since it is fused.

3. Check/replace the Engine Coolant Temperature (ECT) Switch, not the ECT Sensor. To test the ECT Switch, remove the electrical connector. Using a multimeter, set to ohms, check for continuity across the terminals of the switch with the engine cold. The switch should not have continuity, while the coolant is below 189 degrees F. Start the engine and allow it to reach normal operating temperature. Stop the engine and check for continuity again. The ECT Switch should show continuity, when the coolant temperature reaches 196 to 203 degrees F, and above. If the switch fails to show continuity above this temperature, replace it.

If the radiator fan runs all the time, the ECT Switch will likely show continuity below 189 degrees F. This situation will, also, require replacing the switch.


4. Check/replace the radiator fan relay, which is usually located in the under hood fuse/relay box. It's easiest to use a Power Probe II, in conjunction with a multimeter. Power Probe II will power up the relay, while the multimeter will test for continuity (ohms).