Electric Fan Motor
 

1999 Grand Cherokee w/ 4.0L. The electric cooling fan was going through a
slow death (decreasing RPM's) so I recently replaced.

The new fan worked fine for several days then it ran constantly after the
engine was shut off. For several days I just unplugged the fan so it would
not drain my battery. Now when I plug it back in, it does not work at all,
even when the temperature guage reads 210+.

The temperature guage, thermostat and relay appear to working correctly.

Does the electric fan take its signal from the temperature sensor at the
thermostat or is there another sensor that could be causing the problem?

Any suggestions?

- Tom R

Re: Electric Fan Motor
 

Well assuming its the same layout as my 4.0 , the electric fan gets its
signal from the temp sensor on the thermostat housing, the gauge gets its
signal from a sending unit on the after left hand side of the engine. the
gauge and fan don't share the sensor/sending units. Sounds to me like
either your temp sensor (on the t-stat housing) or the relay for it has bit
the dust. Eliminate the fan by connecting it directly to the battery, if it
spins then you know its good.

Snow... "Don Cherry for Prime Minister"


"Tom R" <tomr@noreply.com> wrote in message
news:ec6sc.19789$fF3.505534@bgtnsc05-news.ops.worldnet.att.net...
> 1999 Grand Cherokee w/ 4.0L. The electric cooling fan was going through a
> slow death (decreasing RPM's) so I recently replaced.
>
> The new fan worked fine for several days then it ran constantly after the
> engine was shut off. For several days I just unplugged the fan so it would
> not drain my battery. Now when I plug it back in, it does not work at all,
> even when the temperature guage reads 210+.
>
> The temperature guage, thermostat and relay appear to working correctly.
>
> Does the electric fan take its signal from the temperature sensor at the
> thermostat or is there another sensor that could be causing the problem?
>
> Any suggestions?
>
> - Tom R
>
>
>

Re: Electric Fan Motor
 

Well assuming its the same layout as my 4.0 , the electric fan gets its
signal from the temp sensor on the thermostat housing, the gauge gets its
signal from a sending unit on the after left hand side of the engine. the
gauge and fan don't share the sensor/sending units. Sounds to me like
either your temp sensor (on the t-stat housing) or the relay for it has bit
the dust. Eliminate the fan by connecting it directly to the battery, if it
spins then you know its good.

Snow... "Don Cherry for Prime Minister"


"Tom R" <tomr@noreply.com> wrote in message
news:ec6sc.19789$fF3.505534@bgtnsc05-news.ops.worldnet.att.net...
> 1999 Grand Cherokee w/ 4.0L. The electric cooling fan was going through a
> slow death (decreasing RPM's) so I recently replaced.
>
> The new fan worked fine for several days then it ran constantly after the
> engine was shut off. For several days I just unplugged the fan so it would
> not drain my battery. Now when I plug it back in, it does not work at all,
> even when the temperature guage reads 210+.
>
> The temperature guage, thermostat and relay appear to working correctly.
>
> Does the electric fan take its signal from the temperature sensor at the
> thermostat or is there another sensor that could be causing the problem?
>
> Any suggestions?
>
> - Tom R
>
>
>

Re: Electric Fan Motor
 

Well assuming its the same layout as my 4.0 , the electric fan gets its
signal from the temp sensor on the thermostat housing, the gauge gets its
signal from a sending unit on the after left hand side of the engine. the
gauge and fan don't share the sensor/sending units. Sounds to me like
either your temp sensor (on the t-stat housing) or the relay for it has bit
the dust. Eliminate the fan by connecting it directly to the battery, if it
spins then you know its good.

Snow... "Don Cherry for Prime Minister"


"Tom R" <tomr@noreply.com> wrote in message
news:ec6sc.19789$fF3.505534@bgtnsc05-news.ops.worldnet.att.net...
> 1999 Grand Cherokee w/ 4.0L. The electric cooling fan was going through a
> slow death (decreasing RPM's) so I recently replaced.
>
> The new fan worked fine for several days then it ran constantly after the
> engine was shut off. For several days I just unplugged the fan so it would
> not drain my battery. Now when I plug it back in, it does not work at all,
> even when the temperature guage reads 210+.
>
> The temperature guage, thermostat and relay appear to working correctly.
>
> Does the electric fan take its signal from the temperature sensor at the
> thermostat or is there another sensor that could be causing the problem?
>
> Any suggestions?
>
> - Tom R
>
>
>

Re: Electric Fan Motor
 

Well assuming its the same layout as my 4.0 , the electric fan gets its
signal from the temp sensor on the thermostat housing, the gauge gets its
signal from a sending unit on the after left hand side of the engine. the
gauge and fan don't share the sensor/sending units. Sounds to me like
either your temp sensor (on the t-stat housing) or the relay for it has bit
the dust. Eliminate the fan by connecting it directly to the battery, if it
spins then you know its good.

Snow... "Don Cherry for Prime Minister"


"Tom R" <tomr@noreply.com> wrote in message
news:ec6sc.19789$fF3.505534@bgtnsc05-news.ops.worldnet.att.net...
> 1999 Grand Cherokee w/ 4.0L. The electric cooling fan was going through a
> slow death (decreasing RPM's) so I recently replaced.
>
> The new fan worked fine for several days then it ran constantly after the
> engine was shut off. For several days I just unplugged the fan so it would
> not drain my battery. Now when I plug it back in, it does not work at all,
> even when the temperature guage reads 210+.
>
> The temperature guage, thermostat and relay appear to working correctly.
>
> Does the electric fan take its signal from the temperature sensor at the
> thermostat or is there another sensor that could be causing the problem?
>
> Any suggestions?
>
> - Tom R
>
>
>

Re: Electric Fan Motor
 

http://www.----------.com/coolingFan.pdf
God Bless America, ßill O|||||||O
mailto:--------------------

Tom R wrote:
>
> 1999 Grand Cherokee w/ 4.0L. The electric cooling fan was going through a
> slow death (decreasing RPM's) so I recently replaced.
>
> The new fan worked fine for several days then it ran constantly after the
> engine was shut off. For several days I just unplugged the fan so it would
> not drain my battery. Now when I plug it back in, it does not work at all,
> even when the temperature guage reads 210+.
>
> The temperature guage, thermostat and relay appear to working correctly.
>
> Does the electric fan take its signal from the temperature sensor at the
> thermostat or is there another sensor that could be causing the problem?
>
> Any suggestions?
>
> - Tom R

Re: Electric Fan Motor
 

http://www.----------.com/coolingFan.pdf
God Bless America, ßill O|||||||O
mailto:--------------------

Tom R wrote:
>
> 1999 Grand Cherokee w/ 4.0L. The electric cooling fan was going through a
> slow death (decreasing RPM's) so I recently replaced.
>
> The new fan worked fine for several days then it ran constantly after the
> engine was shut off. For several days I just unplugged the fan so it would
> not drain my battery. Now when I plug it back in, it does not work at all,
> even when the temperature guage reads 210+.
>
> The temperature guage, thermostat and relay appear to working correctly.
>
> Does the electric fan take its signal from the temperature sensor at the
> thermostat or is there another sensor that could be causing the problem?
>
> Any suggestions?
>
> - Tom R

Re: Electric Fan Motor
 

http://www.----------.com/coolingFan.pdf
God Bless America, ßill O|||||||O
mailto:--------------------

Tom R wrote:
>
> 1999 Grand Cherokee w/ 4.0L. The electric cooling fan was going through a
> slow death (decreasing RPM's) so I recently replaced.
>
> The new fan worked fine for several days then it ran constantly after the
> engine was shut off. For several days I just unplugged the fan so it would
> not drain my battery. Now when I plug it back in, it does not work at all,
> even when the temperature guage reads 210+.
>
> The temperature guage, thermostat and relay appear to working correctly.
>
> Does the electric fan take its signal from the temperature sensor at the
> thermostat or is there another sensor that could be causing the problem?
>
> Any suggestions?
>
> - Tom R

Re: Electric Fan Motor
 

http://www.----------.com/coolingFan.pdf
God Bless America, ßill O|||||||O
mailto:--------------------

Tom R wrote:
>
> 1999 Grand Cherokee w/ 4.0L. The electric cooling fan was going through a
> slow death (decreasing RPM's) so I recently replaced.
>
> The new fan worked fine for several days then it ran constantly after the
> engine was shut off. For several days I just unplugged the fan so it would
> not drain my battery. Now when I plug it back in, it does not work at all,
> even when the temperature guage reads 210+.
>
> The temperature guage, thermostat and relay appear to working correctly.
>
> Does the electric fan take its signal from the temperature sensor at the
> thermostat or is there another sensor that could be causing the problem?
>
> Any suggestions?
>
> - Tom R

Re: Electric Fan Motor
 

I already tested the fan & relay, they both are OK. I switched out the
Coolant Temperature Sensor today and still no luck.

Now I am wondering now if it could be the thermostat. I know the CTS is in
the same housing as the thermostat, but is it upstream of the thermostat?

Tom R.

"Snow" <snowball_2004@msn.com> wrote in message
news:848sc.9996$sr3.117197@news20.bellglobal.com.. .
> Well assuming its the same layout as my 4.0 , the electric fan gets its
> signal from the temp sensor on the thermostat housing, the gauge gets its
> signal from a sending unit on the after left hand side of the engine. the
> gauge and fan don't share the sensor/sending units. Sounds to me like
> either your temp sensor (on the t-stat housing) or the relay for it has
bit
> the dust. Eliminate the fan by connecting it directly to the battery, if
it
> spins then you know its good.
>
> Snow... "Don Cherry for Prime Minister"
>
>
> "Tom R" <tomr@noreply.com> wrote in message
> news:ec6sc.19789$fF3.505534@bgtnsc05-news.ops.worldnet.att.net...
> > 1999 Grand Cherokee w/ 4.0L. The electric cooling fan was going through
a
> > slow death (decreasing RPM's) so I recently replaced.
> >
> > The new fan worked fine for several days then it ran constantly after
the
> > engine was shut off. For several days I just unplugged the fan so it
would
> > not drain my battery. Now when I plug it back in, it does not work at
all,
> > even when the temperature guage reads 210+.
> >
> > The temperature guage, thermostat and relay appear to working correctly.
> >
> > Does the electric fan take its signal from the temperature sensor at the
> > thermostat or is there another sensor that could be causing the problem?
> >
> > Any suggestions?
> >
> > - Tom R
> >
> >
> >
>
>