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GeoffBooth
07-19-2010, 07:44 PM
95 4.0 SE. Something going on with the AC. Works fine for about 30 seconds. Then starts cycling on / off. Then Fans die out, radio goes off TAC goes to 0, All kind of faults start coming up, slight squeal from the belt and if you let it carry on the engine cuts out. If you turn the AC off it runs fine.
Any ideaís on this one?

Rineheitzgabot
07-19-2010, 08:09 PM
Rodents chewed through wire harness.

Les Parker
07-20-2010, 02:27 PM
Maybe a seized compressor ?:(

GeoffBooth
07-21-2010, 05:46 AM
Hi Les,
I really appreciate your imput. I drove the car 50 miles yesterday to get a better feel for what it is doing. The ac pump seems like it's abouy to lock but it's the power drain I don'y get. Here is what she is doing.
AC starts cycling on/off some times rapidly sometimes stays off for several seconds.
Noise coming from the AC clutch as though something catches each revolution.
Belt squeaks slightly when engaged, clutch and belt get very hot. This is probably the pump going out. Itís what happens next that throws me. Blower fans fade out, TAC goes to zero, radio shuts down, all kind of faults appear on dash and eventually the motor will shut off. Massive power drain. Turn off the AC and it will recover and run fine. The battery was very low. Barely managed to restart. Recharged the battery and drove it 50 miles mostly without Ac running. No problem. Sat it on the drive with everything turned on and it did the same but didnít shut down the motor. Probably because there was more juice in the battery.
Any ideaís? Could the alternator be bad also or maybe the belt was slipping along with a low battery shut down the systems?

GeoffBooth
07-23-2010, 05:00 AM
Both alternator & Ac pump look like they could be the originals. When the pump is engaged it seems like it is taking too much to drive it but. When is starts to shut down the electrics, if the cause is the pump clutch pulling all the current, you would think it would recover as soon as it disengages. I was thinking the clutch was the first thing that shut down. Iíll check that out to be sure. Apart from the clutch, may be pressure switch I canít think of any other ac parts that is reliant on power. Iíve switched the head and relay. What would happen if the switch went bad so it couldnít cycle off when it got up to pressure? The clutch gets very hot. If you wet it, it will sizzle. If it is the alternator, why no red light? Iíve read about testing the alternator voltage / amperage output with a meter. Canít think of a safe way to do that. Anybody know?

Les Parker
07-23-2010, 09:47 AM
Geoff,

Have you checked the level of refridgerant in the system?
The pressure switch, located in the A/C pipe by the reciever dryer, may also not be functioning.
If you have a worn/burnt out fan clutch it would be acting much the same as the grounding of a feed wire.
Check the R134 level first and resistance of the compressor clutch.

Hope this helps.

GeoffBooth
07-24-2010, 12:39 PM
Hi Les,
Hooked up a gauge to the large pipe, small connecter ( the cold one) I believe this is the low side.
To begin with it read 35psi
Started engine, blowers on low, the pump was cycling normally, blowers on full. Rose to 48psi. Only one condenser fan kicked in. Pump cycled rarely. Blowers on low, dropped slowly to 39psi.
But the pump was cycling less frequently than at the beginning.
Ran it for 20 minutes blowers mostly on high then shut engine off. The fan clutch was reasonably cool to the touch and turned reasonably easily. None of the previous problems happened through this time. Thing is though The gauge slowly rose to 90psi and stayed there.
Started engine , blowers on low drops slowly to 45psi. Blowers on high 55psi. Ran it 5 minutes didnít cycle. Shut down engine. Slowly rises to 90psi and after 45 minutes it now read 100psi.
None of this sounds right

GeoffBooth
07-28-2010, 06:15 AM
Ok then, may be this is norman. Just the system Equalizing
pressure when shut off and the ambient temp etc.

Could be something to do with the condenser fans may be. Only saw one running on high. Nothing on low speed but they used to work before. Now they don't run at all. High or low.

Could this cause the problem?

Les Parker
07-29-2010, 09:20 AM
Have you tested the A/C fan temp switch?
Also I suggest checking the refridgerant and compressor oil levels.
Are there any leaks from the system?
Has this been converted to the later R131a ?

greghaugen
05-10-2011, 03:14 PM
With all the bizarre electrical symptoms make sure the relays in the engine-compartment fuse box are good. You could try replacing the A/C relays just for good measure, even though you may hear them clicking. Also, the circuit board itself may have been cooked and causing weird problems. Several traces had overheated on mine and I think had contributed to spotty A/C compressor performance.The 38A fuse box circuit boards commonly fail. Refer to rangerovers.net for more info.

Cheers,
Greg