Dumb question (1 Viewer)

[pkarr]

This sounds stupid, but is there a way to test wether or not an airconditioning system is working when its cold outside? I've got an appointment to take an FJ80 for a second test drive, and I would like to know if the A/C works. The last time I looked at it, it turned the A/C on, the compressor engaged, and the idle bump up worked, but it was cold then too. Any Ideas?

Also I noticed that when backing up, the stering kind of pulsed, whats causing that? Thanks

 

[High Desert]

Don't think the a/c will work if it is cold enough that the thermostat for the a/c thinks the interior is already cold.

You might run the heater wide open for awhile then put the circulation deal on re-circulate and turn on the a/c: see if cold air is created quickly. Would think if it is cold it would not be outside air but A/C air, (cause the vents are on re-circulate). Seems like it would test the a/c but I dunno for sure.

I dunno about power steering deal, all of the older ones pulse some, level could be low.

Quick story

Friend of mine is a Porsche "tech", I was at his dealership BSing with him when a salesman came and got him to talk to a customer that was test driving a new 911, the customer was complaining that the A/C was blowing warm air.

It was like 25 degrees outside, the car was cold,my buddy the Tech explained to the "buyer"; the german climate control was blowing hot air to get the interior UP to normal A/C temp, the termostate climate control did not allow the a/c to cool down to 25... Cruiser is problably doing the same thing.

 

[zcruiser]

A/C will run on my '62 when you push in the blue A/C button, regardless of temperature. There's no "thermostat" that kicks it on and off, you just adjust temperature by sliding more or less heat to be mixed in.

A/C is useful in the winter to dehydrate the air so your windshield will not fog over. Heat + dry air from A/C cycle makes for good defrosting. Newer cars automatically turn on A/C even at cold temps whenever you kick the control over to the windshield vents only for this very reason. Our 60/62's aren't that refined so you have to do it manually but works just the same.

 

[KLF]

A/C will run on my '62 when you push in the blue A/C button, regardless of temperature.

Actually, this isn't true. There is a thermistor switch that sits in the airbox, directly in front of the evaporator coil. It reads the temperature of the air coming out of the blower duct, and helps the amplifier decide if it's OK to run the compressor. If the incoming air is too cold, it won't allow the compressor to engage. This protects the evaporator coil from icing up. So, High Desert is partially correct that you can trick the AC into thinking it's warmer than it really is, you just need to get it really warm in the cabin, then flip the air inlet control to Recirculate, so it's only circulating warm air across the thermistor.

There's no "thermostat" that kicks it on and off, you just adjust temperature by sliding more or less heat to be mixed in.

Well, this is sorta correct, but the system will cycle on and off more or less as you change the temp control. Besides the thermistor, there is a pressure switch that also controls when the compressor runs or not.

A/C is useful in the winter to dehydrate the air so your windshield will not fog over. Heat + dry air from A/C cycle makes for good defrosting. Newer cars automatically turn on A/C even at cold temps whenever you kick the control over to the windshield vents only for this very reason. Our 60/62's aren't that refined so you have to do it manually but works just the same.

Yes, newer cars will turn on the AC when you push the Defrost button, but the compresor won't kick on until the interior cabin air is warm enough for the air to hold any water vapor. Very cold air can't keep moisture in suspension, it condenses and falls out, which is why your car drools water when the AC is on. Cold air is very dry by nature.

I watched my Lexus do this the other day when it was very cold outside. Started it up, hit the defrost button, the AC light came on automatically. But, when I opened the hood, the compressor wasn't running. It eventually did, though.

 

[zcruiser]

Thanks, I knew it cycled, but wasn't sure what the mechanism was... Makes more sense now...