03 Liberty - Overheating - Help Me

[Tyler knight]

I have an 03 Jeep Liberty that has recently developed an issue overheating. I thought it was the relay so replaced that and the fan still doesn’t come on even at 3/4 on the temp gauge. Now I’m just lost and have no clue. We have let the car run to operating temp and you can see the coolant circulating back into the tank so thermostat seems to be fine, when you start the Jeep cold the fan comes on but then shuts off at about 3/8 on the temp gauge. So no I’m at a loss and use my car for work so I’m stressing quite heavily any help would be appreciated.

 

[LibertyTC]

Could be the temp sensor.
When you turn selector to any of the selected A/C * positions or Re-circualation mode, does the fan run & A/C compressor cycle on and off?

 

[uss2defiant]

you can see the coolant circulating back into the tank

Are you referring to the small hose going back to the expansion tank? that's the overflow hose for the coolant to flow back into the system. Seeing flow there is not an indication if the thermostat is good or bad.

 

[Tyler knight]

Just replaced the temp sensor and still no luck are there any regular fuses I should be checking? All it seemed to be to me was the relay

 

[Tyler knight]

And yeah I’m talking about where the hose connects at the fill hole for the tank

 

[Tyler knight]

Sorry for so many replies keep forgetting stuff but no turning AC on doesn’t get the fan to turn on

 

[LibertyTC]

Do you have the 2003 owners manual? If not I can look the 03 fan fuse up.
Either way everything is labelled in the under the hood power- rectangular box.
My 2004 is a green 40 amp in position #2 for the electrical fan.

 

[Tyler knight]

I don’t have my manual and I did not see anything along the lines of fan in the under the hood cover, is there something else it may be referred to as? I did find a fuse panel in the interior on the side of the dash and some more smaller relays under the hinged cover below steering column.

 

[Big Al]

Could be your fan motor needs replacing. Or the wiring has a bad connection or the plug to the fan is corroded. Starts, but trips out after a few minutes.
See if you turn the fan by hand and see that if it rotates freely.
Could be worn out brushes or a failed bearing.
If it was me, I'd remove the fan or just get 2 wires with a fuse on it to test the fan straight to the battery. Run it for a few minutes to see if it runs smooth.

 

[LibertyTC]

2003-2004 was a cross over year for stuff. Is your fan relay located in the under hood fuse panel ?

 

[Tyler knight]

The fan does turn freely and it seems runs smoothly for I’d say at least 10minutes while warming up but refuses to come on again but I’ll see if I can get some wire together.

 

[Tyler knight]

I don’t “think” so In the under hood pane there is no relay as fan in the diagram, what I replaced was a relay mounted below the fuse box.

 

[LibertyTC]

Is your fan relay located here?

You must be registered for see images attach

 

[Tyler knight]

Yeah that is where it is

 

[LibertyTC]

I'm not the electrical specialist but it would make sense to get power to the fan directly for further testing.
This is where Bill our electrical specialist should chime in & he will, hang in there.

 

[Tyler knight]

Okay I’ve got some wire now and will be wiring it up shortly dinners done so gonna eat then hopefully I’ll have results from that for bill all the help and quick responses are much appreciated fellas

 

[Tyler knight]

And worst case scenario how bad of an idea would it be to just wire the fan to a switch?

 

[LibertyTC]

CanBus system. You got to be very careful here. Without an 03 wiring diagram in front of you, I would not mess with it. Bill is in S/Africa, generally comes on later.
I'm not sure how the 03 relay ties into this mess. You don't want to apply power the wrong way & damage the PCM, power train control module sensor wiring.
I'll see if I can find a similar response of Bill's to the fan issue...stand by.

 

[LibertyTC]

Way too many posts to search through. I'd wait for Bills response. Me too tired now, been a long day.
Bill did mention cautions of single speed fan & correct orientation of power & ground not to get mixed up.

 

[Tyler knight]

Welll shooot guess I may hold off then till he’s got an opportunity to chime in ain’t really got the dough to be riskin it at the moment. Have a good night everybody. Hope to hear from you soon mysterious mister Bill.

 

[Billwill]

Yeah big time difference here in South Africa compared to USA.....9:00 am here now while it is about midnight...of the previous day.. in the USA.

I will climb into the wiring diagrams for the 2003 KJ now and post some suggestions...the Relay for the fan on the 2003 KJ is a Solid State Relay ie. it has none of the mechanical coils and contacts.

They are nice when they work but can be a big pain when they do not work which is why the 2003 KJ is the only year they fitted a Solid State Relay to before deciding to drop it.

Will update this post as I go along!

OK you definitely need to download the 2003 Jeep KJ Service Manual from the link below.

Section 8W has the wiring diagrams. The Index section then shows "Component Locations" whereby you can find the correct logic page eg. "Radiator Fan Motor" gets you to page 8W-30-23.

Fuse #2 40 Amp under the Hood supplies power.

You have replaced the Radiator Fan Relay and the Engine Coolant Temp Sensor...this must be the Sensor shown on Page 8W-30-13 which has the Black/Light Blue wire and the Tan/Black wire connected. This sensor is the only one shown connected to the PCM and it must be working as your Temp Gauge is working.

There may be a Thermal Cutout Switch inside the Fan Motor which cuts out when the Motor gets too hot.
I would suggest you totally disconnect the plug on the Radiator Fan Relay.
Now connect the floating Yellow Wire to the floating Dark Blue/Pink wire inside the plug...this supplies fused +12 volts to the Motor While Black/Orange goes to Ground G112.
The motor should run full speed....let it heat up and see if it cuts out when hot.

This will test that the Motor runs OK.

If so, plug the connector back onto the Solid State Relay.
Use a Multimeter to check that Pin #1 gets +12 volts.
Pin #3 should be Ground.
Pin #2 is supposed to switch to +12 Volts.

Pin #4, Light Green Wire, goes through connector C103 on its way to the PCM....you can find connector C103 location in the Index...Connector Locations...sometimes gives you a nice drawing. Plug and re-plug this connector a few times.

I have no idea what voltage we should expect to see on this wire when engine is running.
It may be Positive with respect to Ground or goes to Ground with respect to +12 Volts.

It may in fact be pulsed by the PCM for Speed Control..you would need an Oscilloscope to check that.

So in summary: If the Motor does not run constantly when +12 volts is applied to it then the Motor is bad. The Light Green Wire going through C103 must be good and connector C2 on the PCM must be clean and firm.

Second worst case is that you use a separate standard relay to power the Motor...the Light Green Wire supplies either +12 volts to the Relay Coil or Ground to the Relay Coil....if this is a pulsing voltage it will not work.

Worst case is you supply Fused +12 volts to the Yellow Wire manually through a Switch to turn the Motor on when you want to. Best to unplug the Radiator Fan connector so no funny volts find their way to the PCM and blow it up!

Section 7 in the Service Manual covers cooling but there is not much mention of the Radiator Fan's operation!

www.colorado4wheel.com/manuals/Jeep/KJ/