AC Blower on High all the time??? [Archive] - The Chrysler Minivan Fan Club Forums

: AC Blower on High all the time???



TWA01TC
11-09-2005, 12:43 AM
Hey guys anyone had this one yet??? 01 T/C LXI, the A/C blower is running on high at all times, in Auto, or in manual, the little setting lights on the blower controll knob move but the blower stays at Max, then get this turn the power to the whole Enviro controls off and guess what.. Blower at MAX.

I have seen somthing similar, and I belive it was a Blower Resistor that had failed...

I didn't see any TSB's on this, figured I would ask you guys before plunking down $$$$ on a resistor from chrysler!!


Thanks

James

AMD Rules
11-09-2005, 12:54 AM
I've had multiple blower resistor failures in several vehicles. In my case however I always lost a few of the lower speeds, and only the upper speeds worked. Happened at least once in my 3rd gen van. In my case the blower didn't work at all though unless the controls were set to fast/high speed.

In your case turning the system off, and having the blower still on high is peculiar. Makes me think the problem may be with the control unit itself, or both.

I don't believe there is a TSB for the blower resistor but perhaps Rich or others may know better.

flybyy
11-09-2005, 05:09 AM
Where is the resistor for this actually located? in the switch mechanism?

DSMLVR
11-09-2005, 09:05 AM
If you have the AC Auto controls, you do not have a resistor, you have a power module. Here are instructions covering both the resistor and the module from the service manual:


BLOWER MOTOR RESISTOR
DESCRIPTION
A blower motor resistor is used on this model when
it is equipped with the manual heater-A/C control
(Fig. 9). Models equipped with the optional Auto-matic
Temperature Control (ATC) use a blower power
module, instead of the blower motor resistor. The
blower motor resistor is installed in a mounting hole
in the heater/AC housing, directly behind the glove
box opening of the instrument panel. The resistor
consists of a molded plastic mounting plate with two
integral connector receptacles. Concealed behind the
mounting plate within the heater/AC housing are
four coiled resistor wires contained within a protec-tive
stamped steel cage. The resistor mounting plate
is secured with two screws to the heater/AC housing
and is accessed for service by rolling down the glove
box from the instrument panel.
The blower motor resistor wires will get hot when
in use. Do not touch the resistor wires or the protec-tive
cage if the blower motor has been running. The
blower motor resistor cannot be adjusted or repaired
and, if faulty or damaged, it must be replaced.
OPERATION
The blower motor resistor is connected to the vehi-cle
electrical system through a dedicated take out
and connector of the instrument panel wire harness.
A second connector receptacle receives the pigtail
wire connector from the blower motor. The blower
motor resistor has multiple resistor wires, each of
which will reduce the current flow through the
blower motor to change the blower motor speed. The
blower motor switch in the manual heater-A/C con-trol
directs the ground path for the blower motor
through the correct resistor wire to obtain the
selected speed. With the blower motor switch in the
lowest speed position, the ground path for the motor
is applied through all of the resistor wires. Each
higher speed selected with the blower motor switch
applies the blower motor ground path through fewer
of the resistor wires, increasing the blower motor
speed. When the blower motor switch is in the high-est
speed position, the blower motor resistor wires
are bypassed and the blower motor receives a direct
path to ground through the blower motor switch. The
blower motor resistor may be diagnosed using con-ventional
diagnostic tools and methods.
DIAGNOSIS AND TESTING - BLOWER MOTOR
RESISTOR
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the instrument panel wire harness
connector for the blower motor resistor and the
blower motor pigtail wire connector from the resistor
connector receptacles.
(3) Check for continuity between each of the
blower motor switch input terminals of the blower
motor resistor and the resistor output terminal. In
each case there should be continuity. If OK, repair
the instrument panel wire harness circuits between
the blower motor switch and the blower motor resis-tor
or the blower motor pigtail wires as required. If
not OK, replace the faulty blower motor resistor.

REMOVAL
WARNING: THE BLOWER MOTOR RESISTOR MAY
GET VERY HOT DURING NORMAL OPERATION. IF
THE BLOWER MOTOR WAS TURNED ON, WAIT
FIVE MINUTES TO ALLOW THE BLOWER MOTOR
RESISTOR TO COOL BEFORE PERFORMING DIAG-NOSIS
OR SERVICE. FAILURE TO TAKE THIS PRE-CAUTION
CAN RESULT IN PERSONAL INJURY.
CAUTION: Do not operate the blower motor with the
blower motor resistor removed from the circuit.
Failure to take this precaution can result in vehicle
damage.
(1) Disconnect and isolate the battery negative
cable.
(2) Open the glove box.
(3) Flex both sides of the glove box bin inward
near the top far enough for the rubber glove box stop
bumpers to clear the sides of the glove box opening,
then roll the glove box downward.
(4) Reach through the glove box opening to access
and disconnect the instrument panel wire harness
connector for the blower motor resistor from the
resistor connector receptacle (Fig. 10).
(5) Reach through the glove box opening to access
and disconnect the blower motor pigtail wire connec-tor
from the resistor connector receptacle.
(6) Remove the two screws that secure the blower
motor resistor to the evaporator housing.
(7) Remove the blower motor resistor from the
evaporator housing.
INSTALLATION
CAUTION: Do not operate the blower motor with the
blower motor resistor removed from the circuit.
Failure to take this precaution can result in vehicle
(1) Position the blower motor resistor into the
evaporator housing.
(2) Install and tighten the two screws that secure
the blower motor resistor to the evaporator housing.
Tighten the screws to 2 Nm (17 in. lbs.).
(3) Reconnect the blower motor pigtail wire con-nector
to the blower motor resistor connector recep-tacle.
(4) Reconnect the instrument panel wire harness
connector for the blower motor resistor to the resistor
connector receptacle.
(5) Flex both sides of the glove box bin inward
near the top far enough for the rubber glove box stop
bumpers to clear the sides of the glove box opening,
then roll the glove box upward.
(6) Close and latch the glove box.
(7) Reconnect the battery negative cable.



POWER MODULE
DESCRIPTION
A blower power module is used on this model when
it is equipped with the optional Automatic Tempera-ture
Control (ATC) (Fig. 22). Models equipped with
the standard manual heater-A/C control use a blower
motor resistor, instead of the blower power module.
The blower power module is installed in a mounting
hole in the evaporator housing, directly behind the
glove box opening of the instrument panel. The mod-ule
consists of a molded plastic mounting plate with
two integral connector receptacles. Concealed behind
the mounting plate within the evaporator housing is
the power module electronic circuitry and a large
finned, heat sink. The module mounting plate is
secured with two screws to the evaporator housing
and is accessed for service by rolling down the glove
box from the instrument panel.
The power module heat sink will get hot when in
use. Do not touch the heat sink if the blower motor
has been running. The blower power module cannot
be adjusted or repaired and, if faulty or damaged, it
must be replaced.
OPERATION
The blower power module is connected to the vehi-cle
electrical system through a dedicated take out
and connector of the instrument panel wire harness.
A second connector receptacle receives the pigtail
wire connector from the blower motor. The blower
power module allows the microprocessor-based Auto-matic
Temperature Control (ATC) heater-A/C control
module to calculate and provide infinitely variable
blower motor speeds based upon either manual
blower switch input or the ATC programming using a
Pulse Width Modulated (PWM) circuit strategy. The
PWM voltage is applied to a comparator circuit
which compares the PWM signal voltage to the
blower motor feedback voltage. The resulting output
drives the power module circuitry, which adjusts the
voltage output received from the blower motor relay
to change or maintain the desired blower speed. The
blower power module is diagnosed using a DRBIIIt
scan tool. Refer to the appropriate diagnostic infor-mation.
(1) Disconnect and isolate the battery negative
cable.
(2) Open the glove box.
(3) Flex both sides of the glove box bin inward
near the top far enough for the rubber glove box stop
bumpers to clear the sides of the glove box opening,
then roll the glove box downward.
(4) Reach through the glove box opening to access
and disconnect the instrument panel wire harness
connector for the power module from the module con-nector
receptacle.
(5) Reach through the glove box opening to access
and disconnect the blower motor pigtail wire connec-tor
from the power module connector receptacle.
(6) Remove the two screws that secure the power
module to the evaporator housing.
(7) Remove the power module from the evaporator
housing.
INSTALLATION
WARNING: ON VEHICLES EQUIPPED WITH AIR-BAGS,
DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-LATE
THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-TEM
CAPACITOR TO DISCHARGE BEFORE PER-FORMING
FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-CAUTIONS
COULD RESULT IN ACCIDENTAL AIR-BAG
DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Position the power module into the evaporator
housing.
(2) Install and tighten the two screws that secure
the power module to the evaporator housing. Tighten
the screws to 2 Nm (18 in. lbs.).
(3) Reconnect the blower motor pigtail wire con-nector
to the power module connector receptacle.
(4) Reconnect the instrument panel wire harness
connector for the power module to the module con-nector
receptacle.
(5) Flex both sides of the glove box bin inward
near the top far enough for the rubber glove box stop
bumpers to clear the sides of the glove box opening,
then roll the glove box upward.
(6) Close and latch the glove box.
(7) Reconnect the battery negative cable.

AMD Rules
11-09-2005, 06:15 PM
Bingo. Rich to the rescue. I knew he'd have good information :thumb:

TWA01TC
11-10-2005, 06:17 PM
Any one know??? is the dealer the only place to get/use a DRBIIIt scanner?? I tried the scanner from the local parts store, but no luck, it was generic and only would only pull engine and transmission fault codes.

sellinghomes4u
11-11-2005, 08:14 AM
You can get full scanners from many of the high end tool suppliers but be aware that these will COST you big time around $2000 or more.
Larry

TWA01TC
11-11-2005, 05:41 PM
Just to end this Thread and help anyone with the same problem in the future. I gambled and just replaced the Blower power module, as I was pretty sure that was the problem. Bingo, Fan works fine now in all modes. FYI it was part #5179985AA, $40.54 Very easy to replace took all of 60sec, as per instructions above.... Thanks for the help Rich and the rest!!!

James

DSMLVR
11-12-2005, 09:16 AM
Thank you James for your follow up reply. I am sure it will help others on here.

flybyy
11-13-2005, 12:16 AM
Is there a separate resistor pack for the rear air blower switch as well or does one resistor pack control both?

DSMLVR
11-13-2005, 09:41 AM
That is a great question. To summurize the following book( well almost) I am posting:
There is a relay in front that controls it and there IS a resistor in the back ( inside the right D-pillar trim). Again, that is with the manual HVAC. The autoAC control units have the power module in it's place, like the front.
Here it is from the 2002 service manual. This should cover 2001-2005 for sure. I would imagine that the pre 2001 vans operate basicly the same way. I do not have the Service manuals for them.


BLOWER MOTOR RELAY
DESCRIPTION
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
The blower motor relay (Fig. 5) is a International
Standards Organization (ISO) mini-relay. Relays con-forming
to the ISO specifications have common phys-ical
dimensions, current capacities, terminal
patterns, and terminal functions. The ISO mini-relay
terminal functions are the same as a conventional
ISO relay. However, the ISO mini-relay terminal pat-tern
(or footprint) is different, the current capacity is
lower, and the physical dimensions are smaller than
those of the conventional ISO relay. The blower
motor relay is located in the Intelligent Power Mod-ule
(IPM), which is in the engine compartment near
the battery. See the fuse and relay layout map
molded into the inner surface of the IPM cover for
compressor clutch relay identification and location.
The black, molded plastic case is the most visible
component of the blower motor relay. Five male
spade-type terminals extend from the bottom of the
base to connect the relay to the vehicle electrical sys-tem,
and the ISO designation for each terminal is
molded into the base adjacent to each terminal. The
ISO terminal designations are as follows:
30 (Common Feed) - This terminal is con-nected
to the movable contact point of the relay.
85 (Coil Ground) - This terminal is connected
to the ground feed side of the relay control coil.
86 (Coil Battery) - This terminal is connected
to the battery feed side of the relay control coil.
87 (Normally Open) - This terminal is con-nected
to the normally open fixed contact point of the
relay.
87A (Normally Closed) - This terminal is con-nected
to the normally closed fixed contact point of
the relay.
The factory-installed blower motor relay cannot be
adjusted or repaired. If the relay is damaged or
faulty, it must be replaced.
OPERATION
The blower motor relay is an electromechanical
switch that uses a low current input from the Front
Control Module (FCM) to control the high current
output to the blower motor resistor (manual heater-A/
C control) or blower power module (automatic heat-er-
A/C control). The movable common feed contact
point is held against the fixed normally closed con-tact
point by spring pressure. When the relay coil is

energized, an electromagnetic field is produced by the
coil windings. This electromagnetic field draws the
movable relay contact point away from the fixed nor-mally
closed contact point, and holds it against the
fixed normally open contact point. When the relay
coil is de-energized, spring pressure returns the mov-able
contact point back against the fixed normally
closed contact point. The resistor or diode is con-nected
in parallel with the relay coil in the relay, and
helps to dissipate voltage spikes and electromagnetic
interference that can be generated as the electromag-netic
field of the relay coil collapses.

The blower motor relay terminals are connected to
the vehicle electrical system through a receptacle in
the Intelligent Power Module (IPM). The inputs and
outputs of the compressor clutch relay include:
The common feed terminal (30) receives a bat-tery
current input from the battery through a B(+)
circuit at all times.
The coil ground terminal (85) receives a ground
input through the front/rear blower motor relay con-trol
circuit only when the FCM electronically pulls
the control circuit to ground.
The coil battery terminal (86) receives a battery
current input from the battery through a B(+) circuit
at all times.
The normally open terminal (87) provides a bat-tery
current output to the blower motor resistor
(manual heater-A/C control) or blower power module
(automatic heater-A/C control) through a fuse in the
IPM on the fused rear blower motor relay output cir-cuit
only when the blower motor relay coil is ener-gized.
The normally closed terminal (87A) is not con-nected
to any circuit in this application, but provides
a battery current output only when the blower motor
relay coil is de-energized.
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, further details
on wire harness routing and retention, as well as
pin-out and location views for the various wire har-ness
connectors, splices, and grounds.
DIAGNOSIS AND TESTING - BLOWER MOTOR
RELAY
The rear blower motor relay (Fig. 6) is located in
the Intelligent Power Module (IPM), which is in the
engine compartment near the battery. See the fuse
and relay layout map molded into the inner surface
of the IPM cover for rear blower motor relay identi-fication
and location. Remove the relay from the IPM
to perform the following tests:
(1) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 2. If not OK, replace the faulty relay.
(2) Resistance between terminals 85 and 86 (elec-tromagnet)
should be 75 5 ohms. If OK, go to Step
3. If not OK, replace the faulty relay.
(3) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, use a DRBIIIt scan tool to perform
further diagnosis of the relay circuits. Refer to the
appropriate diagnostic information. If not OK,
replace the faulty relay.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Unlatch and remove the cover from the Intelli-gent
Power Module (IPM)
BLOWER MOTOR RELAY
(3) See the fuse and relay layout map molded into
the inner surface of the IPM cover for rear blower
motor relay identification and location.
(4) Remove the rear blower motor relay from the
IPM.
INSTALLATION
(1) See the fuse and relay layout map molded into
the inner surface of the Intelligent Power Module
(IPM) cover for rear blower motor relay identification
and location.
(2) Position the rear blower motor relay to the
proper receptacle in the IPM.
(3) Align the rear blower motor relay terminals
with the terminal cavities in the IPM relay recepta-cle.
(4) Push down firmly on the rear blower motor
relay until the terminals are fully seated in the ter-minal
cavities in the IPM receptacle.
(5) Install and latch the cover onto the IPM.
(6) Reconnect the battery negative cable.
BLOWER MOTOR RESISTOR
DESCRIPTION
A blower motor resistor is used on this model when
it is equipped with the manual heater-A/C control
(Fig. 8). Models equipped with the optional Auto-matic
Temperature Control (ATC) use a blower power
module, instead of the blower motor resistor. The
blower motor resistor is installed in a mounting hole
on the back of the rear heater-A/C unit housing,
directly above the expansion valve. The resistor con-sists
of a molded plastic mounting plate with an inte-gral
connector receptacle. Concealed behind the
mounting plate within the rear heater-A/C unit hous-ing
are two coiled resistor wires contained within a
protective stamped steel cage. The resistor mounting
plate is secured with two screws to the rear heater-A/
C unit housing and is accessed for service by
removing the right quarter and D-pillar trim panels.
The blower motor resistor wires will get hot when
in use. Do not touch the resistor wires or the protec-tive
cage if the blower motor has been running. The
blower motor resistor cannot be adjusted or repaired
and, if faulty or damaged, it must be replaced.
OPERATION
The blower motor resistor is connected to the vehi-cle
electrical system through a dedicated take out
and connector of the rear HVAC wire harness. The
blower motor resistor has two resistor wires, each of
which will reduce the current flow through the
blower motor to change the blower motor speed. The
blower motor switch in the manual heater-A/C con-
trol directs the ground path for the blower motor
through the correct resistor wire to obtain the
selected speed. With the blower motor switch in the
lowest speed position, the ground path for the motor
is applied through both resistor wires. Each higher
speed selected with the blower motor switch applies
the blower motor ground path through fewer of the
resistor wires, increasing the blower motor speed.
When the blower motor switch is in the highest
speed position, the blower motor resistor wires are
bypassed and the blower motor receives a direct path
to ground through the blower motor switch. The
blower motor resistor may be diagnosed using con-ventional
diagnostic tools and methods.

DIAGNOSIS AND TESTING - BLOWER MOTOR
RESISTOR
Refer to the appropriate wiring information. The
wiring information includes wiring diagrams, proper
wire and connector repair procedures, details of wire
harness routing and retention, connector pin-out
information and location views for the various wire
harness connectors, splices and grounds.
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the rear HVAC wire harness con-nector
for the blower motor resistor from the resistor
connector receptacle.
(3) Check for continuity between each of the
blower motor switch input terminals of the blower
motor resistor and the resistor output terminal. In
each case there should be continuity. If OK, repair
the wire harness circuits between the blower motor
switch and the blower motor resistor or the blower
motor pigtail wires as required. If not OK, replace
the faulty blower motor resistor.
REMOVAL
WARNING: THE BLOWER MOTOR RESISTOR MAY
GET VERY HOT DURING NORMAL OPERATION. IF
THE BLOWER MOTOR WAS TURNED ON, WAIT
FIVE MINUTES TO ALLOW THE BLOWER MOTOR
RESISTOR TO COOL BEFORE PERFORMING DIAG-NOSIS
OR SERVICE. FAILURE TO TAKE THIS PRE-CAUTION
CAN RESULT IN PERSONAL INJURY.
CAUTION: Do not operate the blower motor with the
blower motor resistor removed from the circuit.
Failure to take this precaution can result in vehicle
damage.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the right quarter trim panel and right
D-pillar trim panel from the quarter inner panel.
(Refer to 23 - BODY/INTERIOR/QUARTER TRIM
PANEL - REMOVAL).
(3) Disconnect the rear HVAC wire harness con-nector
for the blower motor resistor from the resistor
connector receptacle (Fig. 9).
(4) Remove the two screws that secure the blower
motor resistor to the rear heater-A/C unit housing.
(5) Remove the blower motor resistor from the rear
heater-A/C unit housing.
INSTALLATION
CAUTION: Do not operate the blower motor with the
blower motor resistor removed from the circuit.
Failure to take this precaution can result in vehicle
damage.
(1) Position the blower motor resistor into the rear
heater-A/C unit housing.
(2) Install and tighten the two screws that secure
the blower motor resistor to the rear heater-A/C unit
housing. Tighten the screws to 2 Nm (17 in. lbs.).
(3) Reconnect the rear HVAC wire harness connec-tor
for the blower motor resistor to the resistor con-nector
receptacle.
(4) Reinstall the right quarter trim panel and
right D-pillar trim panel onto the quarter inner
panel. (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - INSTALLATION).
(5) Reconnect the battery negative cable.

flybyy
11-13-2005, 10:53 AM
wow... thx..

daffoo
06-08-2009, 10:54 AM
I was troubleshooting my front A/C blower not working (2001 DGC ES, 3.8L, ATC). The compressor was cycling and the rear blower was working fine. As it turned out there was a ground problem in the wiring harness going to the front blower. Here is how I narrowed it down...

The voltage off the ATC controller in the dash was varying, the blower control module voltage was varying, the fuse was good and the relay was good. NOTE: the dealership will try to sell you a resistor module even when you have an automatic temperature control (ATC) system. The part in question is labeled "Module" in their parts inventory and you have to be very specific with the parts guy! In my case the "Module" did not need replacine.

So I assumed it was the blower motor and bought a replacement at AutoZone ($90). Before removing the old blower I decided to connect the new blower up before pulling the old one out. Nothing. I reconnected the old blower, accidentally bumped the wiring harness and the fan started working. Then it was a matter of tracking it down and finding the faulty ground.

Hope this helps.