2003 Dodge Caravan A/C Clutch problem

Tiny
SULLIVANTRAININGSYSTEMS
  • MEMBER
  • 2003 DODGE CARAVAN
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 140,000 MILES
I have a full 12VDC at the a/c clutch, but the clutch won't engage. Ohmed out clutch and got 8.7 ohms - normal. Voltmeter reads normal, test lite lights up, but clutch won't engage. Any ideas?

Dan Sullivan
Sunday, May 17th, 2009 AT 11:26 AM

15 Replies

Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
Check the ground circuit
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Monday, May 18th, 2009 AT 6:14 AM
Tiny
SULLIVANTRAININGSYSTEMS
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I have full voltage at the connector. The ground is intact - I don't have an open.
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Monday, May 18th, 2009 AT 7:23 AM
Tiny
BMRFIXIT
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If you have battery power at one wire and good ground at the other
than clutch is no good
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Monday, May 18th, 2009 AT 7:58 PM
Tiny
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Clutch engages fine with external power and ohms out at 8.7 ©.
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Monday, May 18th, 2009 AT 8:46 PM
Tiny
BMRFIXIT
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I don't understand if you have battery power and good ground than no need for an external power if you are applying power for it to work than check system if low on 134A
check and clear codes and than should kick in
do a code check
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Monday, May 18th, 2009 AT 9:39 PM
Tiny
SULLIVANTRAININGSYSTEMS
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There are no codes. The connector at the compressor has 12V. The positive and ground are both intact. The clutch coil works if powered up. A test light lights up on both [+] and ["”]. Coil resistance is normal (8.7 ©). If you plug in the clutch it won't work?
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Tuesday, May 19th, 2009 AT 5:46 AM
Tiny
BMRFIXIT
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COMPRESSOR CLUTCH COIL
DIAGNOSIS AND TESTING - COMPRESSOR CLUTCH COIL
The air conditioning compressor clutch coil electrical circuit is controlled by the Powertrain Control Module (PCM) through the compressor clutch relay, which is located in the Intelligent Power Module (IPM) in the engine compartment near the battery. Begin testing of a suspected compressor clutch coil problem by performing the preliminary checks.
PRELIMINARY CHECKS
If the compressor clutch will not engage, verify the refrigerant charge level. (Refer to REFRIGERANT - DIAGNOSIS AND TESTING - REFRIGERANT CHARGE LEVEL ). If the refrigerant charge level is OK, go to Step 2. If the refrigerant charge level is not OK, adjust the refrigerant charge as required.
If the a/c compressor clutch still will not engage, disconnect the headlamp and dash wire harness connector for the A/C pressure transducer and check for battery current at the connector with the engine running and the heater-A/C control set to the A/C mode. If OK, go to TESTS. If not OK, use a DRBIII(R) scan tool to perform further diagnosis. Refer to the appropriate diagnostic information.
TESTS
Verify the battery state of charge. (Refer to BATTERY - DIAGNOSIS AND TESTING ).
Connect an ammeter (0 to 10 ampere scale selected) in series with the clutch coil feed terminal. Connect a voltmeter (0 to 20 volt scale selected) to measure voltage across the battery and the clutch coil.
With the heater-A/C control in the A/C mode and the blower at low speed, start the engine and allow it to run at a normal idle speed.
The compressor clutch should engage immediately, and the clutch coil voltage should be within two volts of the battery voltage. If the coil voltage is not within two volts of battery voltage, test the clutch coil feed circuit for excessive voltage drop. If the compressor clutch does not engage, use a DRBIII(R) scan tool to perform further diagnosis. Refer to the appropriate diagnostic information.
With the ambient temperature at 21 ° C (70 ° F), the compressor clutch coil is acceptable if the current draw is 2.0 to 3.7 amperes at 11.5 to 12.5 volts at the clutch coil. If the voltage is more than 12.5 volts, add electrical loads by turning on electrical accessories until the voltage reads below 12.5 volts.
If the compressor clutch coil current reading is zero, the coil is open and must be replaced.
If the compressor clutch coil current reading is four amperes or more, the coil is shorted and must be replaced.
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Tuesday, May 19th, 2009 AT 6:27 AM
Tiny
SULLIVANTRAININGSYSTEMS
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What's baffling is that when you turn on the clutch, you should see 12V at the connector. If you have 12V there, everything else is working right. I have 12V at the connector. The clutch works because I powered it up with a separate battery. 12V at the connector, and a clutch that works.

Plug in the clutch - clutch no work.

?

Where did you get the instructions you provided for the clutch?
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Thursday, May 21st, 2009 AT 4:58 PM
Tiny
BMRFIXIT
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What is your low and high ac line pressure
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Thursday, May 21st, 2009 AT 7:29 PM
Tiny
SULLIVANTRAININGSYSTEMS
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Everything is FINE. I have 12V at the clutch connector. The voltage is there. The clutch works if you plug it into another battery. If you plug it back into the vehicle harness, it won't work.

According to the instructions you sent, nothing in the PCM or electronic system has failed, because if it had failed, I wouldn't have 12V at the connector. The directions said to look for voltage - it's there.

?
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Thursday, May 21st, 2009 AT 7:52 PM
Tiny
DOCFIXIT
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Try this pull A/C relay jumper from terminal 30 to 87 does clutch engage?
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Tuesday, May 26th, 2009 AT 12:06 PM
Tiny
SULLIVANTRAININGSYSTEMS
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Used the ammeter and jumped 30-87. No change.
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Tuesday, May 26th, 2009 AT 12:56 PM
Tiny
DOCFIXIT
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What is voltage from terminal 30 to ground?
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Tuesday, May 26th, 2009 AT 1:12 PM
Tiny
SULLIVANTRAININGSYSTEMS
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12V terminal 30 to ground. As before, 12V at the (+) and (-) of the clutch connector. An LED testlite lights up for pos and ground.
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Tuesday, May 26th, 2009 AT 1:47 PM
Tiny
SULLIVANTRAININGSYSTEMS
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I found the problem. It was corrosion about 4 inches back from the connector in the positive wire. The digital voltmeter cannot see this problem and all of the checks the manual calls for were good. I used a special tool that works with a meter to find it. Apparently someone poked a hole with a sharp tool and the wire turned green.

Thank you. You can keep the $20.
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Tuesday, May 26th, 2009 AT 8:34 PM

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