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Radiator fan assembly purchase advise (also a thanks)

 
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Old 25 Apr 2016, 05:56 pm
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Default Radiator fan assembly purchase advise (also a thanks)

Hi All!

First of al, as a newbie Cruiser, l I'd like to introduce myself and also thanks this forum.

I came to US on beginning august/2015 for a graduate studies. In the end of that month I bought a 2008 PT Cruiser Touring with 102.028 miles from an university's student that was leaving US. I did evaluate the car and it is in a good shape.... no signal of accident, clean carfax, , no corrosion, good brakes, suspension, etc. The only think I have noticed is that it was using a green antifreeze and the low speed radiator fan rotation wasn't working, making AC to no work when engine is in idle. After googling around, I noticed that this is a common problem, and the previous owner gave me a huge discount.

Thanks to this forum I was able to flush and refill the coolant with HOAT Zerex-G05 before winter. About five/six months after purchase I had a cylinder 3 misfire. I give a shot by replacing myself the spark plug kit with the help of this forum. So I bought a good tool kit, a torque wrench, etc. The old spark plug kit was very worn (I think they were original). With the new one, the engine check light went away

Back to the radiator fan, I notice that the fan is never being started. So I did a test. I disconnected the fan connector, wired it to measure voltage with a voltimeter and started the engine. When AC switch is on, I get the 14.4V on the low speed output, but the high speed output is always down (0.35V).

I waited until the temperature gauge stop in the middle between H & C and measured again. Only the low speed output had voltage to turn fan on (14.4V).

Should the high speed output have voltage to turn fan on, right ?

Interesting is that my car never overheated... it just had some leakage that I used K-SEAL to fix it.

I think I'll replace the fan with the complete assembly that comes with relays... what do you guys think? Also, is it normal to not have a car overheated without a working fan ? Well... I live in a small college town with almost no traffic and everything is near....

Now the car is with 105.300 miles. It's time to replace the radiator fan, to further work on AC.
I'm willing to by this one, do you recommend it ?

More Information for DORMAN 620052

Another thing, I'd like to know how can I disconnect the big 4 wire connector that comes from PDC. The gray one in the picture. How do I disconnect it ?
BTW, the zip ties I added it after disconnecting the other connector (the one that goes to fan motor). The picture is attached to this post.

Thanks a lot to everyone.
Lucas
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File Type: jpg fan-connector.jpg (91.1 KB, 28 views)
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Old 25 Apr 2016, 06:54 pm
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Default Re: Radiator fan assembly purchase advise (also a thanks)

Welcome to the Forum from PA.

You have to have enough freon charge in the AC system for the high speed on the fan to kick on.
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Old 25 Apr 2016, 07:38 pm
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Default Re: Radiator fan assembly purchase advise (also a thanks)

Hi Joe:

Quote:
Originally Posted by JoeX View Post
You have to have enough freon charge in the AC system for the high speed on the fan to kick on.
That makes perfect sense. Last week I've tested the low pressure sensor from AC system, because the compressor is not kick in. I jumped the sensor's connector and seems that the compressor kicked in. So I assume that the car is low on freon. I'll tackle with that latter after replacing the radiator fan.

BTW, can you help me on how to disconnect the 4-wire radiator fan connector ? Do you think the radiator fan assembly I pointed out is a good purchase ?

thanks a lot!!
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Old 25 Apr 2016, 08:15 pm
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Default Re: Radiator fan assembly purchase advise (also a thanks)

Welcome from Texas. The Dorman fan is a good choice. Are you sure you need to replace it? Sounds like you are low on refrigerant and that's the reason that the fan is not engaging. On the picture of the connector, it looks like you should depress the tab and pull it apart. Sometime if the connector has not been apart, they will stick and be difficult to separate.
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Old 25 Apr 2016, 08:53 pm
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Default Re: Radiator fan assembly purchase advise (also a thanks)

Welcome Lucas,
First of all, the plug. You need to push on the tab to unlock the connector coming from the relays. Watch this video. He shows how to disconnect the plug at 4:20.
https://youtu.be/EwquTLC2Ink


If you know your electronics, the PCM actually sinks current to turn the relay on.

Looking at the relay from the front of the vehicle, there are 4 terminals on the relay socket. +12 Volts is on the passenger side of the terminal block (you can check it with a volt meter) and the PCM shorts it to ground with the driver's side terminal. This closes the relay. When the relay closes, +12V is routed from the terminal closest to the radiator to the terminal towards the back of the car. That terminal is attached to the brush of the fan motor and should read about 1 Ohm. Mine read 0.78 Ohms on the high speed relay and infinite on the low speed relay. That showed me why the low speed fan wasn't working at low speed. My last hope was that a wire broke between the relay and the connector, but that wire showed 0 Ohms so the low speed brush was the cause of the failed motor and I needed a new fan assembly

Here's the pinout to the relay terminal blocks after pulling the relays out:


A new fan assembly cost $83 + shipping from Rock Auto or about $140 from a local auto parts store. For the time between ordering the replacement fan and when it arrived, I made a manual switch that turned the high speed fan on with a switch inside the car. You need to put a 100 Ohm resistor between the +12V and the relay control line to the PCM, otherwise the PCM will throw a "cooling circuit 2 fault" code because the PCM won't sense current flowing through the relay circuit. You can also control the relay by taking the relay return line and grounding it with the swich inside the car. That means you are only switching 100 mA instead of 10-20 Amps through the switch.

Here's a schematic of the "cheater circuit". Use this only if you know your electronics. Miswiring can cause melted switches, wires and a bad day for your PT Cruiser:



This is not for a Turbo model. The fan on the Turbo models is further controlled by a PWM controller which sends variable width pulses to the fan. This gives a more "continuously variable" speed to the fan.

Here's the relay logic for a properly working 2nd generation non-turbo PT Cruiser


When I first got my PT Cruiser, the A/C was short cycling. With the temporary fix (manual fan switch) the A/C worked fine. Now that I have a properly working fan assembly, the A/C works fine all the time and the fan is operating fully automatically again.

If you are going to route any wires that run power to the fan, use 12 gauge wire as a minimum and keep wire lengths as short as practically possible. 12 gauge lugs and sockets (yellow colored) are available at most auto stores.

Good luck.
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Old 25 Apr 2016, 08:58 pm
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Default Re: Radiator fan assembly purchase advise (also a thanks)

Hi from Indiana!

Quote:
Originally Posted by VsandFords View Post
Welcome from Texas. The Dorman fan is a good choice. Are you sure you need to replace it? Sounds like you are low on refrigerant and that's the reason that the fan is not engaging. On the picture of the connector, it looks like you should depress the tab and pull it apart. Sometime if the connector has not been apart, they will stick and be difficult to separate.
Well... I'm pretty sure. I have disconnected the connector that goes directly to fan motor (that comes from relays) and put a voltmeter for measuring. When I turn on AC system (pressing the AC button), the 14.4V shows up. Connecting the fan again and doing the same test, the fan doesn't spin.

Moreover, when I bought this car the AC was working (freon was in a good pressure) and the fan wasn't already working.

thanks a lot!
Lucas

PS: I've visited Austin on november/2015. What a nice city!! I love it!!
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Old 25 Apr 2016, 09:35 pm
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Default Re: Radiator fan assembly purchase advise (also a thanks)

Hello RSRocket...

That wasn't an explanation... that was a lecture!! Thanks....
I'll not go so far on wiring a manual switch... But that's a clever idea!

Quote:
Originally Posted by rsrocket1 View Post
Looking at the relay from the front of the vehicle, there are 4 terminals on the relay socket. +12 Volts is on the passenger side of the terminal block (you can check it with a volt meter) and the PCM shorts it to ground with the driver's side terminal. This closes the relay. When the relay closes, +12V is routed from the terminal closest to the radiator to the terminal towards the back of the car. That terminal is attached to the brush of the fan motor and should read about 1 Ohm. Mine read 0.78 Ohms on the high speed relay and infinite on the low speed relay. That showed me why the low speed fan wasn't working at low speed. My last hope was that a wire broke between the relay and the connector, but that wire showed 0 Ohms so the low speed brush was the cause of the failed motor and I needed a new fan assembly
Good luck.
So, this means that if I jump (with a, say, 14 AWG) the +12V connector towards the car's front to the connector towards the back (towards the motor), the fan should start on each speed, right ? See the attached picture. The jumper would be the thick red lines I've draw over your picture.

Thanks a lot!
Lucas
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Old 26 Apr 2016, 11:31 am
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Default Re: Radiator fan assembly purchase advise (also a thanks)

Lucas,
You are correct with your diagram. You can also check the resistance from the terminal "To Low Speed Brushes" and "To High Speed Brushes" with an Ohm meter to ground (the bolt sticking out next to the hood release latch which is labeled "for jumper use" or something like that). It should read about 1 Ohm. If it shows an open, the brushes on that side are bad.
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Old 29 Apr 2016, 10:43 am
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Default Re: Radiator fan assembly purchase advise (also a thanks)

Hello!

Quote:
Originally Posted by rsrocket1 View Post
You are correct with your diagram. You can also check the resistance from the terminal "To Low Speed Brushes" and "To High Speed Brushes" with an Ohm meter to ground (the bolt sticking out next to the hood release latch which is labeled "for jumper use" or something like that). It should read about 1 Ohm. If it shows an open, the brushes on that side are bad.
Yesterday I had some time and did the testing. First I read the resistance on both terminal. As I was imagining, between terminal "To Low Speed Brushes" to ground is a open circuit (infinit resistance). These brushes are gone.

But, from terminal "To High Speed Brushes" to ground it was about 0.5 Ohm. So I jumped this terminal to +12V on battery and the fan started spin beautifuly in high speed.... without any vibration or squeaky sound... very silent.... strong as a tornado!

I wonder if it isn't hard to take out the high speed connector and low speed connector from the three terminal connector bellow the fan assembly and switch between them. Doing so, I would have a high speed fan when the car system starts the low speed. Since both low speed and high speed relay are from the same type/part number/specification, this new wiring would work.

What I mean is, disassembling the connector:



Take out the terminal number 1 and 3 and switch between them (see the bellow schema)




Does anybody did this already ? Did you think it is hard to do?

Thanks a lot,
Lucas
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Old 02 May 2016, 04:20 pm
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Default Re: Radiator fan assembly purchase advise (also a thanks)

Lucas,
You can do this, but what you are doing is substituting the low speed with the high speed fan functions. That means any time your PCM intends for only the high speed fan to turn on, you are not running the fan at all.

According to the logic chart from the manual, if you swapped pins on the 3 pin connector you won't get the fan running with the A/C off while running above 44 mph. You will also get no fan running when the A/C is on at any vehicle speed. The former is possibly OK but the latter will be fatal in stop and go traffic.

My recommendation would be
  1. Get a new fan assembly OR replace the brushes. This is a very good thread on what the brushes look like and what it takes to replace them. The good pictures are in the attachments on the second page of messages. Here's another thread showing what the worn out brushes look like.
  2. In the mean time, use the "cheater" circuit I showed in the earlier post to manually control the fan on high speed only with just one 22 gauge wire leading into the passenger compartment. Be sure to "fool" the PCM with a 100 Ohm resistor across the relay socket pins so you don't get the MIL code.
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