(5) In st all the two A/C-h eater con trol retaining
scr ews. Tighten t he screws to 2 N·m (17 in. lbs.).
(6) In st all the center bezel onto the instrument
pa nel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - INSTAL-
LATION).
(7) Reconnect t he negat ive batt ery cable.
A/CPRESSURETRANS-
DU CER
DESCRIPTION
The A/C pressur e tran sducer is in st alled on th e liq-
uid line fitting located at the top of th e receiver/drier
(Fig. 9). A rubber O-ring seals t he conn ection
between the tra nsducer and the fitting. Th ree termi-
nals with in a molded plastic connector recepta cle on
the top of th e tra nsducer connect it to the vehicle
electrical system t hrough a wir e lea d a nd connector.
The A/C pressure transducer ca nnot be adjusted or
repaired a nd, if faulty or dam aged, it must be
repla ced.
OPERATION
The A/C pr essu re transducer monitors th e pres-
su res in the high side of the refrigera nt system
through it s connect ion to a fitting on the liquid line.
The transducer will change its interna l resistan ce in
response to the pressu res it monitors. The ATC con-
trol m odu le provides a five volt refer ence signal and
monitors the out pu t volta ge of the tra nsducer on the
transdu cer ret urn circuit to deter mine refr iger ant
pr essu re. The ATC m odule is pr epr ogra mmed to
respond to th is and ot her sensor inputs by contr olling
the operation of the a ir conditioning compressor
clutch a nd the auxiliary radiat or cooling fan t o help
opt imize air conditionin g system per forman ce an d to
pr otect the syst em com pon ents from damage. The
A/C pressure transdu cer input to the ATC module
also pr event s the A/C compressor clutch from enga g-
ing when t he ambient tempera ture is below 0.556° C
(33° F) due to t he pressur e/temperature relat ionship
of the refrigerant.
The A/C pressu re transducer is dia gnosed by per-
forming t he ATC Function Test usin g th e DRBIII!
sca n tool. Refer to Body Dia gnostic Procedu res.
The A/C pressure transducer ca nnot be adjusted or
repaired a nd, if faulty or dam aged, it must be
repla ced.
DI AGN OSI S AN D T EST I N G
A/ CPRESSURETRANSDUCER
The A/C pressure t ransducer is test ed usin g a
DRBII I! sca n tool. Refer t o Body Dia gnostic Proce-
du res. Before t est ing the A/C pressure transdu cer, be
certa in th at th e tr ansducer wire har ness connections
are clea n of cor rosion and properly connected. For
the air conditioning system to oper ate, an A/C pr es-
su re transducer voltage reading between 0.7 and 4.56
volt s is required. Volt age ou tside t his ran ge indicate
a low or high refriger ant system pressure con dition
to the ATC contr ol modu le. The cont rol m odu le is
pr ogrammed to respond t o a low or high refr iger ant
system pressur e by suppressing opera tion of the com-
pr essor. Refer t o the A/C Pressure Tra nsducer Volt-
age chart for the possible condition indica ted by the
transdu cer volt age readings.
Fig. 9 A/C Pressure Transducer
1 - A/C PRESSURE TRANSDUCER
2 - PIEZORESISTIVE ELEMENT
3 - WIRE CONNECTOR
24 - 14 CONTROLS-FRONT VA
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