Workshop Manuals Factory service & repair Aston Martin
Aston Martin DB7 Factory Workshop Manual Volume 2: Electrics, Body and Air Conditioning (1994-1998)04 · Air conditioning
04 · Heating & A/C

Blower Motor Test

Make
Aston Martin
Model
DB7 Factory Workshop Manual Volume 2: Electrics, Body and Air Conditioning
Year
1994–1998
Section
System fault diagnosis › Blower Motor Test
Air conditioningBlower Motor Test

Blower Motor Test

Face Level: Hot Face Temperature Demand Switch: Minimum

Differential temp. 28 0 to 200mV
Temperature demand 35 0 to 200mV
Note: Allow the servo motors to come to rest before checking voltage levels. Typical figures are given in brackets.
Mode Switch RH Control LH Control RH Feedback LH Feedback
Position Pin No. 32 Pin No. 31 Pin No. 33 Pin No. 22
Low 1 - 2V (1.77V) 1 - 2V (1.77V) 4 - 6V (5.8V) 4 - 6V (5.63V)
Med 2 - 3V (2.28V) 2 - 3V (2.27V) 3 - 5V (3.7V) 3 - 5V (3.4V)
High 1 - 2v (1.17V) 1 - 2V (1.19V) 1 - 2V (1.22V) 1 - 2V (1.27V)

Set Face Differential Pot. to Mid Point

Mode Switch RH Control LH Control RH Feedback LH Feedback
Position Pin No. 32 Pin No. 31 Pin No. 33 Pin No. 22
Low 1 - 2V (1.24V) 1 - 2V (1.27V) 6.5 - 9V (8.7V) 6.5 - 9V (8.7V)
Medium 1 - 2V (1.4V) 1 - 2V (1.4V) 6.9 - 9V (7.5V) 6.5 - 9V (7.5V)
High 2 - 3V (2.2V) 2 - 3V (2.2V) 3 - 5V (4.1V) 3 - 5V (4.0V)

Set Face Differential Pot. to Cold Face

Mode Switch RH Control LH Control RH Feedback LH Feedback
Position Pin No. 32 Pin No. 31 Pin No. 33 Pin No. 22
Low 1 - 2V (1.67V) 1 - 2V(1.63V) 6.5 - 9V(6.25) 6.5 - 9V(6. IV)
Medium 2 - 3V(2.17) 2 - 3V(2.1V) 3 - 5V(4.25V) 3 - 5V(4.2V)
High 2 - 3V(2.3V) 2 - 3V(2.2V) 3 - 5V (3.7V) 3 - 5V(3.5V)

Open Water Temperature Switch Needs

Set Temperature Demand Switch to Midpoint Pin No. 35 1.43 -145V

RH Servo control Pin 32 0 - 0.5V
LH Servo control Pin 31 0 - 0.5V

Short Water Temperature Switch Leads

Mode Switch: Low
Clutch output Pin 20 9.3 - 12.3V
RH Servo control Pin 32 1 - 2V
LH Servo control Pin 31 1 - 2V
Set diff to hot face Pin 28 0 - 200mV
Set temp demand to minimum Pin 35 0 - 200mV
Recirc. output Pin 3 9.3 - 12.3V
High speed relays Pin 16 0 - 200mV
Water valve solenoid Pin 17 9.3 - 12.3V
Centre vent solenoid Pin 18 9.3 - 12.3V
Defrost output Pin 27 0 - 500mV
MODE SWITCH: DEFROST Pin 27 150 - 350mV
High speed relays Pin 16 9.3-12.3V
Lower feedback pot. Pin 29 2.709-3.100V
Upper feedback pot. Pin 30 1.714 -2.014V
MODE SWITCH: OFF Pin 44 0-IV
Recirc. output Pin 3 9.3-12.3V

Parts & tools for this job For 1994 Aston Martin DB7

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