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Author Topic: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,  (Read 5056 times)

Offline debnal

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2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« on: December 29, 2010, 01:02:00 PM »
And it's only 20 degrees out! I have to pull the fuse to stop it.
Found the relay down behind the grill and unplugged/replugged the connector a few times but no change.
I read there is a TSB for this problem but don't know any details.
Should I replace the relay? Anybody know? Looks like it's pop-riveted to the bumper beam?
I don't want to buy a relay if it's something else.
 

Offline nickb2

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #1 on: December 29, 2010, 03:08:41 PM »
Have you tried turning off the A/C? If the fan turns off you may have an A/C issue. Do you have a check engine code? If your check engine light is on and you don't have a scanner you can always use the key on 3 time cycle method and read codes on digital odometer readout. If you have a p1491 code that would narrow down your diagnostics.

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« Last Edit: December 29, 2010, 03:20:06 PM by nickb2 »
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Offline Mobile Dan

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #2 on: December 29, 2010, 03:15:29 PM »
When that relay goes bad, it's in one of two ways.....fan won't come on, or won't go off. I haven't seen any other cause for "fans stay on" on that model vehicle. Change the relay.

Offline nickb2

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #3 on: December 29, 2010, 03:22:00 PM »
@danica, I have seen a/c pressure tranducers cause this also.
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Offline debnal

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #4 on: December 29, 2010, 04:20:52 PM »
Thanks for your replies!
I haven't been running the A/C but tried shutting off the heater (that's all we need in Wisconsin this time of the year) and no change.
I DO get the P1491 code with the 3-on-cycle method.
Guess I'll replace the relay and see if that does it (hope).
Thanks Again!

Offline kev2

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #5 on: December 29, 2010, 04:44:38 PM »

FYI the defrost mode WILL utilize the A/C system....

spent time in New Berlin Wis ......  loved it

Offline NickD

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #6 on: December 29, 2010, 05:05:17 PM »
You're not running your AC in Wisconsin?  Well, neither am I.

According to Nick's posted circuit diagrams, your only source of voltage to your cooling fans is via the coolant fan relay, and runs continuous because it is connected to always hot.  They do that to cool down an overheated engine even after you switch off the key.  PCM is confusing with that shorting jumper shown, really don't know who draws these circuits, but obviously the PCM plays a role in switching on the coolant fans via the ETC or via a command from the climate control with the AC switched on.  AC command only runs when the ignition is on with the blower motor switched on.

Is because of these kinds of nebulous circuit diagrams find myself tracing circuits in the vehicle.

Going to make a wild guess that since you pulled what you thought was the cooling fan relay, and the fans still ran, with the ignition off, perhaps you didn't pull the correct relay.  That relay was headed south anyway as carbon arcing causes excessive contact resistance that translates into heat that can and does weld the contacts together.  But you did find the correct fuse.  May have to trace back your blower motor hot wire, that's one way to find the correct relay,

Offline Jim Fairbanks

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #7 on: December 29, 2010, 05:49:34 PM »
I think he found the right one...Jim

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Offline billr

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #8 on: December 29, 2010, 06:04:44 PM »
I agree with Jim, that looks like the pop-riveted one described.  Is there an electrical connector there that he can remove and probe for coil voltage always-on?

Offline debnal

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #9 on: December 29, 2010, 06:56:48 PM »
Yep, that's a picture of it. 
There is a connector on the relay that I unplugged and sprayed a little WD40 into before plugging/unplugging a few times to try and improve the connections there.
The fans don't run with the relay unplugged but always run when plugged.   

Offline nickb2

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #10 on: December 29, 2010, 08:17:41 PM »
I'm not saying it isn't the relay, but ppl here will know I am a HUGE fan of diagnosing BEFORE replacing, cuz ya never know and parts being the price they are in THIS economy, well...
here is a troubleshooting chart specific to your trouble, that's why I asked if you had that code.
Step #1 is to verify that DRB scanner will turn on relay, we will assume it does as you have no scanner and power is obviously on to fan!
step#2 is to wiggle fan relay harness as fan operates with DRB scanner commanding it on. Since you have no DRB scanner, just wiggle the wiring to and from harness and see if power cuts out, this will indicate a short is harness of fan relay.
follow the next picture charts if above step keeps power alive to fan.

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Offline nickb2

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #11 on: December 29, 2010, 08:28:08 PM »
Here is a chart for step 1 through 12 anyways to make this a complete post. I am also testing out some software at the same time to see how my jpeg's and pdf's work, just can't seem to get rid of black contrast screen on all my downloads, before I had watermarks now this, oh well, better than nothing. Still readable I hope. This post is a downloadable PDF with entire trouble shooting chart and possible causes for code p1491.

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« Last Edit: December 29, 2010, 08:32:32 PM by nickb2 »
When it don't work, hit it!!!


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Offline NickD

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #12 on: December 29, 2010, 09:07:53 PM »
Sure looks like a solid state relay with that finned heat sink.  More than likely uses a power MOSFET transistor that shorted out.  Didn't catch that part about unplugging this relay killing the blower motor.  Certainly not an open circuit due to corroded contacts, motor wouldn't run at all.  Two seconds with my test equipment, would know precisely what it is.

If it's like GM, that relay module would blow first before the fuse does, can be caused by one or both of the fan motors taking too long to build up to speed.  Have to determine if that relay is the culprit or the victim.

Offline NickD

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #13 on: December 29, 2010, 09:29:33 PM »


Bet its solid state, 43 bucks at rockauto.com.  a precaution with these, can be activated with a logic lever PCM output only outputting a microampere of current.  Don't try an electrical mechanical relay that can pull 0.1 to 0.2 amps, may blow your PCM for even more headaches.

Would definitely do a current check on the radiator fans, may buy a new relay, and it will pop when the fans go on.

Offline Mobile Dan

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Re: 2001 Chrysler Town & Country Cooling Fan Runs Continuously,
« Reply #14 on: December 29, 2010, 09:38:05 PM »
The solid state radiator fan relay is controlled by the Powertrain Control Module (PCM) by way of a Pulse Width Modulated (PWM) signal. The relay control circuit supplies a 12 volt signal to the PCM. The PCM then pulses the ground circuit to achieve fan on time. The relay provides a voltage to the fan motors which is proportional to the pulse width it receives from the PCM. The duty cycle ranges from 30% for low speed operation, then ramps-up to 100% for high speed operation.


Pin 4 at the relay is the control circuit..DB/VT dark blue with violet tracer. While connected, (fans running) cut that wire in a place that will be easy to repair.  I don't recommend removing the wire from the connector.  Since the PCM makes the fan run by grounding the relay (PWM), this should make the fan stop if the PCM is turning on the relay. If the fan does not stop, I think you need a new relay.

 

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