Question about Cars & Trucks
Looks like the low pressure switch gets power from a 10amp ac fuse. Power then goes to the ac relay which is powered on by the ac heat controller on the dash. Power then goes thru the high pressure switch to the compressor. The ac relay is grounded to the body. Do you have power on the lite and dark green wires going into the relay and is it grounded ?
Posted on Jul 26, 2013
SOURCE: 99 Suburban A/C Not working
The A/C pressue switch may be bad as well. Also the mode switch on the control head inside the vehicle. There are many other exsisting problems pertaining to a/c. I suggest a manual from Auto Zone for many faults can be noted especially wiring can be at fault
Posted on May 23, 2009
The air gap may be too wide between the clutch disc and plate. It usually happens from wear. You can test this possibility by engaging the clutch electrically as you have done and then push on the disc slightly with the handle of a hammer or screwdriver. Be careful not to get your hand or fingers too close while the engine is running. Basically you are helping the magnetic field pull the disc in. I hope this helps.
Posted on Aug 19, 2009
IF YOU HAVE 100 PSI ON LOW SIDE.YOU HAVE A EXCESSIVE AIR AND MOISTURE IN THE SYSTEM.YOU HAVE TO HAVE SYSTEM DISCHARGED AT AC SHOP OR DEALERSHIP.YOU HAVE TO REPLACE ACCUMULATOR OR RECEIVER DRIER.HAVE SYSTEM EVACUATE.THEN RECHARGED.SEE YOUR AC IS NOT TO COME ON LONG AS YOUR LOW SIDE TO HIGH.YOUR LOW PRESSURE SWITCH. IS NOT GOING TO CLOSE CIRCUIT TO TURN ON COMPRESSOR.UNTIL PRESSURE DROP AT A CERTAIN LOW PRESSURE.
Posted on Aug 25, 2009
SOURCE: put in a new dash
well here's the theory first
you PCM (powertrain control module) decides when and IF it wants the A/C compressor to run
when the PCM wants the compressor to operate it supplies a GROUND for the A/C relay
Therefore... FIRST lets see if the PCM is commanding the relay
the easiest way to to remove the a/c relay
install a small wire to pin 85 of the relay...it SHOULD be marked on the relay
re-install the relay
they make cool little adapters for this but they cost about $100 off the tool truck
then using a regular test light, install one end to the vehicle battery and the other to that little ground wire
turn your a/c on, engine running obviously, and see if your test light illuminates
if it does not, then we have to repeat this same test but this time at the PCM pin # 1 connector #3
again, if no illumination then we need to find out why the PCM is not commanding the clutch operation
if however, it does not illuminate at the relay BUT lights at the PCM then you have an open in the circuit between the PCM and the a/c relay
good luck and keep me posted!
Posted on May 21, 2010
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