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sprinkles08, ASE Certified Technician
Category: Chrysler
Satisfied Customers: 22661
Experience:  ASE Master & Advanced level certified, Chrysler Master Certified, Trans and Hybrid Specialist
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how to replace tempterature sending unit on a 2005 pt cruiser

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how to replace tempterature sending unit on a 2005 pt cruiser

Hello and welcome to JustAnswer!


What temperature sending unit are you needing to replace?

What kind of problems are you having?

Customer: replied 7 years ago.

I replaced the fan assembly about 2/3 weeks ago and every thing worked fine! I could hear the fan motor shutting down after I turned off engine. Last week the motor started heating up and the fan motor stopped running. Sometimes it would run and some time it wouldn't. I checked all the connections, ok, put it back together still the fan motor will not rub and engine heats up.

An online advice says it could be the temp. sending unit? I torn into it again and it looks almost impossible to change without taking a lot off?

But the temperature gauges always works, correct? If the temperature gauge works and the engine light isn't on then the coolant sensor is ok.


Have you checked fuses?


Do you have a voltmeter to do some electrical testing?

Customer: replied 7 years ago.

The guages has always worked and the light and chime comes on when it gets to hot!

I looked at the fuse, looked, ok.

I was told that the radiator fan cooling motor was controlled ,off/on by the temperature sending unit, is this not correct? Sometimes the fan will come on and run for a while and then shut and will not come back on until after it cools down.

No, that's not correct. The coolant temperature sensor just tells the engine controller how hot the coolant is when it leaves the head. That is it's only function. The engine controller turns the fan on and off depending on coolant temperature, a/c pressure, and trans temperature, using a couple relays.


If you have a voltmeter we can do some electrical testing while it's acting up and find out what is going on.


Customer: replied 7 years ago.
I do not have a volt meter here. What if I replaced hi an low relays?

You could try that, but it's unlikely that one relay has failed, two failed relays at one time would be very rare.


Customer: replied 7 years ago.
what are you asking me to check with the volt meter? When I finished putting it back together yesterday the fan never came on but it got hot!

I haven't asked you to check anything with a voltmeter yet because you said you didn't have one.


The first thing you would need to do is start it and let it run for a minute with the a/c on, until the fan would normally be running, and check for power and ground at the fan connector.


Customer: replied 7 years ago.

You know that is not an easy request because of where the connector is located? It will take me some time to go get my volt meter and check this! What is this tell me if there is no power?

Will you still be around when I get it checked, say a hour or 2?

It only takes a minute to slide underneath and unplug the connector and check for power and ground. This is the first step that needs to be done.


If there is power and ground then we will then go to testing at the relays.


I'll be around four about another 9 or 10 hours today, just let me know your results and we'll go from there.


Customer: replied 7 years ago.

I have a volt meter but it is at my sons home! I was a mechanic along time ago but I am retired and gave all my tools to my son!

How will I get back with you?

Just come back and reply to this same question as you have been already, and I will get notification that you responded to me and we'll pick up where we left off.


Customer: replied 7 years ago.

Hey , I found what it was when I started to disconnect the connector! Something is not making good contact? I can wiggle the connector a little and it will stop and again it will start!

Now my a/c doesnt't seem to be working properly, sounds like the clutch is clicking off/on and not cooling! Is there something to do with the fan to cause this. I know when the fan stopped working the a/c stopped cooling. It was working great before?

By the way the voltage was 13.68 and 12.04!

The poor connection definitely sounds like the problem! You can hopefully use a small pick to tighten the pin grip a little bit on the female side of the connector and take care of that.


The a/c problem shoudl be directly related to the fan not working. When the fan isn't able to come on at idle and low speeds to pull air through the condensor it will cause the a/c high side pressure to climb high enough that the air won't cool, and the compressor will start to cycle. If you have it in gear alot of times you can actually feel the engine drag down when the compressor engages and disengages because the pressure is so high. Once you get the fan working again you should find your a/c comes back.

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