03 Liberty - Overheating - Help Me

[uss2defiant]

one thing to add is if your SSD relay is the same size as Tim's picture then you need to upgrade it to the beefier replacement.
i don't remember if it was a TSB or a recall.

 

[uss2defiant]

I've scoped the PWM from the PCM and it wasn't a PWM at all and it was just a 12V signal, if memory serves me right, this was way back in 2010.

 

[uss2defiant]

dealing w/ the SSR is a pain and Bill's suggestions are great.

I would start by inspecting the rad e-fan connector. They are known to go bad and have bad connection causing extreme heat in the connector and melting it.
Whether or not you see any melted plasting, probe the rad e-fan connector that is 2 pins and check if there is 12V. This is with engine and AC on.
If there isn't any 12V, check the fuse.
If the above is all good then most likely the sensors, pcm, etc are good except for the actual fan itself.

Hopefully you have items with you that you can supply 12V to the rad e-fan to see if the fan is bad.

 

[Billwill]

I've scoped the PWM from the PCM and it wasn't a PWM at all and it was just a 12V signal, if memory serves me right, this was way back in 2010.

Thanks for that...I doubted it would be using PWM as that is major overkill but you would need an Oscilloscope and know how to use it!. This makes life a lot easier now to trace!

 

[Billwill]

dealing w/ the SSR is a pain and Bill's suggestions are great.

I would start by inspecting the rad e-fan connector. They are known to go bad and have bad connection causing extreme heat in the connector and melting it.
Whether or not you see any melted plasting, probe the rad e-fan connector that is 2 pins and check if there is 12V. This is with engine and AC on.
If there isn't any 12V, check the fuse.
If the above is all good then most likely the sensors, pcm, etc are good except for the actual fan itself.

Hopefully you have items with you that you can supply 12V to the rad e-fan to see if the fan is bad.

Good idea....always a good chance that the pins on the Motor Plug could have melted due to the large amount of current going through there!

 

[Tyler knight]

Hi good to meet ya, I tried jumping the wires in the plug but the fan still doesn’t come on, I don’t have a multimeter to test those wires but all connectors seem to be good. So wiring it with fused 12v I would do from negative on battery to black on fan. Then positive to yellow with switch and fuse inline and that should be okay?

 

[Tyler knight]

Sorry didn’t see your msg before my previous reply regarding plug possibly being messed up I don’t know if messing with connectors changed something but I just retested and now using a test light I do get power to the fan with ac on and the fan does come on and stay on, I’m currently letting it run to see if it’ll come on without the ac on.

 

[Tyler knight]

Was testing past the plug so I think all is good with the plug, fan itself, coolant temp sensor, and relay correct? Or it wouldn’t come on with ac?

 

[Tyler knight]

Oh my sweet baby Jesus I think we found the problem boys tried turning ac on again after running for a bit and fan didn’t come on so I tested and test light does light up testing past plug despite fan not spinning, gave the fan a little nudge and she started spinning. Sooo I need a new radiator fan?

 

[uss2defiant]

Oh my sweet baby Jesus I think we found the problem boys tried turning ac on again after running for a bit and fan didn’t come on so I tested and test light does light up testing past plug despite fan not spinning, gave the fan a little nudge and she started spinning. Sooo I need a new radiator fan?

yup. sounds like it. unless something was blocking it. intermittent fan spinning is a sign of a bad motor. been there done that.

To clarify about the connector, just look at it where it mates, facing the male pins and the female side. inspect to see if anything is melted.

 

[uss2defiant]

Thanks for that...I doubted it would be using PWM as that is major overkill but you would need an Oscilloscope and know how to use it!. This makes life a lot easier now to trace!

Yes. I borrowed a digital tektronix oscilloscope from my lab.
I've never ever seen/hear the fan change speeds either.

 

[uss2defiant]

Was testing past the plug so I think all is good with the plug, fan itself, coolant temp sensor, and relay correct? Or it wouldn’t come on with ac?

The e-rad fan only comes on at certain conditions.

OPERATION
The electric radiator cooling fan is controlled by the Powertrain Control Module (PCM) through the radiator cooling fan relay. The PCM regulates fan operation based on input from the engine coolant temperature sensor, battery temperature sensor,air
conditioning select switch and vehicle speed. The fan is not energized during engine cranking regardless of the electrical input from the temperature sensors and ,air conditioning switch. However, if engine operation conditions warrant fan engagement, the fan will run once engine starts.

Vehicles Equipped with AC:
In addition to using coolant temperature and battery temperature sensor to control cooling fan operation, the cooling fan will also be engaged when the ,air conditioning system is activated. The relay is also energized when, air conditioning is selected and coolant temperature is above 95° C ( 203° F), or , air conditioning is selected and battery temperature sensor is above 41° C (106°F). It will then de-energize when , air conditioning is selected and coolant temperature is below 92° C (198° F), or , air conditioning is selected and battery temperature is below 38° C (100° F).

 

[Tyler knight]

Since my previous post I’ve tested a few times at the wire just past the plug and consistently the wire is getting power but fan not spinning and a small nudge will get the fan going. And throughly check both plugs on harness and fan and both look bran new to be honest

 

[Big Al]

Great to hear it was an easy fix and you never had to dig into the electrical wiring.

 

[Tyler knight]

It will probably be a few days before I can get a new fan to be for sure but I’m am very glad to have this group and am very appreciative of all your help, still curious to see what bills opinion is as far as the plug/wire getting power, fan not working till nudged.

 

[uss2defiant]

I'm not Bill but anyways

the e-rad fan is most likely a brushed motor, the replacement doorman is a brushed motor....

Given the age of the vehicle, the following could be the cause of the bad motor:
1. the brushes were probably worn down
2. dirt/debris/crud/corrosion build up internally, possibly between the magnets and the armature
3. bad bearing

 

[Billwill]

Yes. I borrowed a digital tektronix oscilloscope from my lab.
I've never ever seen/hear the fan change speeds either.

In the 10 years that I worked in the field for IBM I permanently had a Tektronix Scope in the trunk.....I think that even now I would be able to work it without any hesitation....lovely piece of equipment!

Hardly touched Oscilloscopes in the later years as it was mainly component replacement as called out by diagnostics!

 

[Billwill]

Definitely looks like the Motor is bad if you need to nudge it to get going.

Try get a new one or good one from a Breaker Yard.

You could try opening the Motor up...inspect the bearings/bushes and maybe lubricate or replace them.

And clean the Commutator which is what the Brushes run on...use some fine Emory paper.

The Brushes themselves may be worn down.

Lots of work but worth performing it in an emergency...best to try get a new motor!

 

[Tyler knight]

Alright thank you for the input, in looking for a new/used fan from a salvage yard do you think a 12v drill battery and some wire would be good enough to test a fan at the salvage yard?

 

[uss2defiant]

Alright thank you for the input, in looking for a new/used fan from a salvage yard do you think a 12v drill battery and some wire would be good enough to test a fan at the salvage yard?

I want to say it should be okay as most modern battery packs have over current protection. YMMV