98 caravan ac stuck in defrost position

[marko85]

my 98 caravan ac sytem is stuck in defrost position turn the mode dial and nothing changes i got a code 1 and 3 out of the climate control module. 1 states stuck in defrost and 3 says passenger blend did not reach cold stop. what does this mean and how can i fix it?

[RIP]

I take it the calibration test isn't helping. Inspect the connection on the panel. They are known to melt on 3rd generation vans. Defrost is the default mode when the processor looses power or programming. Try disconnecting the negative battery cable for 2-3 minutes to reset it. Can't help beyond that. Maybe a new panel - Ebay? Hope someone with a factory manual can jump in here.

[mgbmike]

I'm not familiar with the system but here is what the FSM says, maybe someone with more knowledge can help:

DIAGNOSTIC TROUBLE CODE 1 - MODE
ACTUATOR DID NOT REACH “DEFROST”
POSITION
DESCRIPTION
When the HVAC Control Module calibrates the
Mode Door Actuator, it first moves the actuator
toward the DEFROST position. In the DEFROST
position, circuit C37 of the 21 pin connector should
have a value of approximately 0.3 to 0.8 volts. When
the actuator does not reach the DEFROST position,
DTC 1 sets.
DETECTION
When the voltage at C37 is approximately 2 volts
or greater, the DRB IIIt will display the DTC.
POSSIBLE CAUSES
• Mode Door reaches the DEFROST position and
does not respond to changes in the control panel settings.
• Mode Door Feedback Signal circuit is OPEN.
• Mode Door Feedback Signal circuit is SHORTED
to 5 or 12 volts.
• Mode Door is stuck.
• Mode Door Actuator is stuck.
• Mode Door Driver circuit is OPEN.
• Mode Door Driver Circuit is SHORTED to
ground. Diagnostics begin momentarily and then
STOP with no LED’s until the short is removed, and
then both WIPE and INTERMITTENT LED’s flash
simultaneously.
• Mode Door Actuator gear is not properly connected.
• Sensor ground circuit OPEN may set multiple
DTC’s 1, 4, 5, and 8, and defaults to Full Hot and
Defrost. Recirc continues to operate.
If there is air flow in the Defrost position, even
though the DTC indicates that the actuator cannot
reach the Defrost position, there is and open in the
Mode Door Feedback Signal circuit (the door is
moved to the Defrost position attempting to lower the
feedback voltage).
If the Mode Door Actuator fails between Bi-Level
and Mix, both DTC’s 1 and 2 will be set.
If the Mode Door Actuator fails in the Panel Position
and is blowing air in this position, DTC 1 is set.
TEST PROCEDURES
Disconnect the Actuator connector.
(1) Using a voltmeter, measure between pins 1 and
5. If the voltage is not 12 volts 6 1 volt, check the
actuator driver circuits wiring for a short or open circuit.
Measure the voltage between pins 2 and 4. If
the voltage is less than 4 volts, check the 5 volt supply
circuit. Measure the voltage between pins 3 and
4. If the voltage is less than 4.5 volts, check the
actuator feedback circuit.
(2) Remove actuator, and check if the gear pins are
in the correct track on cam or if they are binding. If
OK, go to Step 3. If not OK, repair as necessary.
(3) Check for binding door, if door is binding repair
as necessary. If gears and door are OK, replace
actuator.
(4) Once repairs are completed repeat the Calibration
Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.

DIAGNOSTIC TROUBLE CODE 3 - BLEND/
PASSENGER ACTUATOR DID NOT REACH “COLD”
STOP
DESCRIPTION
When the HVAC Control Module calibrates the
Blend/Passenger Door Actuator, it moves the actuator
toward the HOT position and then toward the COOL
position. In the COOL position, circuit C36 of the 21
pin connector should have a value of approximately
0.6 to 1.2 volts. When the actuator does not reach the
COOL position, DTC 3 sets.
DETECTION
When the voltage at C36 is greater than 2.0 volts,
the DRB IIIt will display the DTC.
POSSIBLE CAUSES
• Blend/Passenger Door reaches the COOL position
and does not respond to changes in control panel
settings.
• Blend/Passenger Feedback Signal circuit is
SHORTED to 5 volts.
• Blend/Passenger Actuator is stuck.
• Blend/Passenger Door is stuck.
• Blend/Passenger Door Actuator Driver circuit is
OPEN.
• Blend/Passenger Door Actuator Drover circuit is
SHORTED to ground. Diagnostics begin momentarily
and then STOP with NO LED’s until the short is
removed, and then both WIPE and INTERMITTENT
LED’s flash simultaneously.
• Battery Voltage is less than 10.0 volts.
If there is air flow (passenger side on Zone control),,
even though the DTC indicates that the actuator
cannot reach the cool position, there is a short to
voltage in the Blend/Passenger Door Feedback Signal
circuit (the door is moved to the Cool position,
attempting to decrease the feedback voltage).
If the Blend/Passenger actuator fails in the Mid
position, both DTC’s 3 and 4 will be set.
If the Blend/Passenger Door/Actuator fails in the
Hot position and is blowing hot air, DTC 3 is set.
TEST PROCEDURES
(1) Check if the correct HVAC control module was
used.
Disconnect the Actuator connector.
(2) Using a voltmeter, measure between pins 1 and
5. If the voltage is not 12 volts 6 1 volt, check the
actuator driver circuits wiring for a short or open circuit.
Measure the voltage between pins 2 and 4. If
the voltage is less than 4 volts, check the 5 volt supply
circuit. Measure the voltage between pins 3 and
4. If the voltage is less than 4.5 volts, check the
actuator feedback circuit.
(3) Remove actuator, and check if gear pins are in
the correct cam track or binding. If OK, go to Step 4.
If not OK, repair as necessary.
(4) Check for binding door, if door is binding repair
as necessary. If gears and door are OK, replace
actuator.
(5) Once repairs are completed repeat the Calibration
Diagnostic and Cooldown test. Repeating the
test is necessary to clear the fault codes.

Mike

[RIP]

Mike - Big thank you. That's one of the few time someone actually did "jump in" with a factory manual and I've been on forums for years.

[mgbmike]

No, thank you RIP for all the help you have given to others. I've only had my van since May and have been fortunate that so far it has no troubles. But I read every forum dealing with third generation vans just to expand my limited knowledge.
Mike