[gregstevens67]

hi fellow disco lovers, have an odd scenario with my o5 hse disco aircon (I am a fridgee by trade) did a compressor ,condenser/drier change on my own hse with rear air, vac it overnight charged system with 900gms 134a system running perfect 15mins then blip the throttle and compressor shuts off and system goes static? disconnect comp check volts 13v at compressor plug it in reading is 9v. pull fuse in glove box for ac and bang back to life. drive disco 20kms on freeway fine then stops again. pull u at lights compressor starts again? all electrical connections are fine operating head pressures are fine, no dtc's. to me it appears the atcu is limiting negative voltage flow to compressor? can anyone shed some light as its doing my head in!!! spoke to stealership an no reset is needed for atcu. appreciate any input.
just have to say seen some bad posts on here about disco's anyone wanting to buy a v8 hse like mine go for it, its the best car ive ever owned and trust me ive had almost 100 cars:beer::beer::beer::beer::beer:!

 

[tlt]

Do you have or need the service manual?

 

[gregstevens67]

yes have the disco 3 cd

 

[gregstevens67]

does anyone know the cut out pressure on the high side pressure switch of the ac cant find it on the cd?

 

[ronscantlin]

I don't know the pressure, but you might be onto something there.... Depending on if the high switch is normally open, or closed, check at idle, then hit the throttle and see what happens to your ohm meter.... It shouldn't change, unless over charged, or blocked... Right?
AND if your high and low side readings are in spec, then that switch is bad...that would explain most of the described behavior.

 

[RoverGuy7]

I don't know the spec on the switch, but keep in mind, this is a variable displacement, clutchless compressor. It is designed to not be fully engaged most of the time.

I would agree that it is probably due to the HVAC limiting voltage, but that is supposed to happen, you just need to figure out why.

Make sure the AC drains are clear and not causing the evap. to freeze over and cause it to cut due to evap temp.