AC Diagnostics

[CrUZida]

Is there such a thing (ie, self diagnosis system)?

In my GS130 wagon, the aircon is fully gassed, and it turns on for about 5 seconds, then trips out (presumably the AC Amplifier is turning it off) and then the AC button LED flashes until you press it again.

Is there a self diagnosis system where it can tell me whats wrong?

Or alternatively a wiring diagram?

[Z2TT]

From what I have heard this is ussually a problem with the A/C Magnetic Clutch relay and replacing it should fix the problem.

[Dale]

I don't think there's a way to get the actual error out of it, but that sounds very typical of not getting a signal from the slip/RPM sensor. If the engine speed varies to the rpm of the air con compressor the AC amplifier assumes the belt or clutch to be slipping so removes power from the magnetic clutch to stop any damage.

A few things could be causing it, but it's most likely that the sensor is unplugged somewhere along the way back to the AC amplifier. Colours of the wires should be easy to identify from the loom side of the 2 wires going into the slip sensor plug, find them at the AC amplifier and check for continuity between there and the plug for the compressor. If there is continuity chances are the sensor itself is stuffed, which you could check with a scope as I believe it's just a pulse output... although I think it's pretty rare for slip sensors to die.

[CraigD]

some new toyota's you can get codes for ac

I too would look at the relay as i have had a few play up

[Gavatron]

You can get codes out of the newer climate control units by holding the AUTO and FRESH/RECIRC buttons while turning the ignition on.

If the light is flashing it is usually to do with the slip sensor like Dale said.

[william]

how do you know the system is fully charged? has it been serviced recently? check for signs of leaks by looking for dye(usually fluro green) at the fittings and around the condenser

i would bridge the pressure switch(usualy located on the high pressure side of the system(small pipe) or on the drier) with a paper clip while the a/c is switched on the compressor should engage and stay engaged

if so either the switch is faulty or there is a gas/pressure related problem

if not there is probably a wiring issue

[CrUZida]

No slip sensor that I remember seeing, only the clutch wire on the unit (will have another check though).

System is fully charged because a) the sensor is SC, and b) when I run +12V directly to clutch it get nice and cold.

Have already tried another relay (assuming its the metal one under dash that clicks when you push the AC button). About 5 seconds after turning the AC on you can hear it unclick.
Is this the relay, or is there one under the bonnet aswell?

Will try the diagnostics as Gav suggested (not holding my breath).


The car does have a rear aircon system, which a previous owner disconnected.
I couldn't see a standard pressure sensor in the line there, but saw some other sensor.
But it doesn't make a difference with this sensor plugged, unplugged, or bridged.

[wilbo666]

You can get codes out of the newer climate control units by holding the AUTO and FRESH/RECIRC buttons while turning the ignition on.

If the light is flashing it is usually to do with the slip sensor like Dale said.

This works on JZZ30 for example...

Should be able to find the guide for soarer around...

Cheers
Wilbo

[Z2TT]

Thing is how will you find the codes and what they mean for the GS130?

[Gavatron]

They will most likely be exactly the same as any locally deliver car with climate control.

[CrUZida]

Yeah, codes are generally the same across most Toyota models.
Its just how to retrieve them that differs from model to model.

[CrUZida]

Just tested, no codes thrown
But it was the auto light that flashed the codes (or lack there of) ,whereas it was the a/c light before

[2jzhilux]

Sounds like the speed sensor in your compressor is detecting slip so it cuts out the compressor which could mean two things either your a/c clutch is slipping or your compressor is locked up and the clutch is trying to cut in and then detecting the difference and cutting it back out.

[CrUZida]

There is no speed sensor on the compressor

[Dale]

Did you look underneath it? Normally they're on the bottom so the wires might have been severed or are tucked up out of view somewhere