Gs300 Mk.1 Air-con Problem

[razagilani]

My series 1 GS300 has a problem with it's AC. It switches on fine but then only runs for 10 seconds before disengaging the compressor. It then stays off for 30-40 seconds and then starts again, but only for the same 10 seconds. It keeps on doing this in the same cycling pattern.

Lexus looked at it today and re-gassed it as they said there was some air in the system but drove 30 miles after and problem remains. I don't think they have the ability to diagnose. Before I took it to Lexus I got Kwik-Fit to re-gas the system so I am confident that gas is not the problem.

As the compressor engages and does it's job i.e. it cools the air very well, my guess is that it may be a faulty sensor telling the compressor to switch off prematurely. This only a guess as I don't pretend to know about this aspect of cars, although I am somewhat interested in mechanicals in general. Hate cars with sensors all over the place. They can ruin a good car.

Am at a bit of a loss. If Lexus can't help, where else do I go? Changed the AC relay just to eliminate it and it is not faulty.

If anybody can shed some light I would be most grateful.

Regards to all.

[legendswraith]

My series 1 GS300 has a problem with it's AC. It switches on fine but then only runs for 10 seconds before disengaging the compressor. It then stays off for 30-40 seconds and then starts again, but only for the same 10 seconds. It keeps on doing this in the same cycling pattern.

Lexus looked at it today and re-gassed it as they said there was some air in the system but drove 30 miles after and problem remains. I don't think they have the ability to diagnose. Before I took it to Lexus I got Kwik-Fit to re-gas the system so I am confident that gas is not the problem.

As the compressor engages and does it's job i.e. it cools the air very well, my guess is that it may be a faulty sensor telling the compressor to switch off prematurely. This only a guess as I don't pretend to know about this aspect of cars, although I am somewhat interested in mechanicals in general. Hate cars with sensors all over the place. They can ruin a good car.

Am at a bit of a loss. If Lexus can't help, where else do I go? Changed the AC relay just to eliminate it and it is not faulty.

If anybody can shed some light I would be most grateful.

Regards to all.

I assume by "disengage" you mean the engine revs drop off back to around 600ish then theres a pause before it starts pick up to the revs for when the air con cuts in. There is a sensor actually on the aircon compressor but it would be a bit of a trial and error swap to find the fault as i don't know the aircon circuit.

If you look here theres a few diagrams may give you some clues http://www.toyodiy.com/parts/p_E_1995_LEXU...QFW_8719.2.html

[razagilani]

My series 1 GS300 has a problem with it's AC. It switches on fine but then only runs for 10 seconds before disengaging the compressor. It then stays off for 30-40 seconds and then starts again, but only for the same 10 seconds. It keeps on doing this in the same cycling pattern.

Lexus looked at it today and re-gassed it as they said there was some air in the system but drove 30 miles after and problem remains. I don't think they have the ability to diagnose. Before I took it to Lexus I got Kwik-Fit to re-gas the system so I am confident that gas is not the problem.

As the compressor engages and does it's job i.e. it cools the air very well, my guess is that it may be a faulty sensor telling the compressor to switch off prematurely. This only a guess as I don't pretend to know about this aspect of cars, although I am somewhat interested in mechanicals in general. Hate cars with sensors all over the place. They can ruin a good car.

Am at a bit of a loss. If Lexus can't help, where else do I go? Changed the AC relay just to eliminate it and it is not faulty.

If anybody can shed some light I would be most grateful.

Regards to all.

I assume by "disengage" you mean the engine revs drop off back to around 600ish then theres a pause before it starts pick up to the revs for when the air con cuts in. There is a sensor actually on the aircon compressor but it would be a bit of a trial and error swap to find the fault as i don't know the aircon circuit.

If you look here theres a few diagrams may give you some clues http://www.toyodiy.com/parts/p_E_1995_LEXU...QFW_8719.2.html

Thanks for the reply, I will try and analyse with help of a friend with a brain. Regards.

[mopar]

My series 1 GS300 has a problem with it's AC. It switches on fine but then only runs for 10 seconds before disengaging the compressor. It then stays off for 30-40 seconds and then starts again, but only for the same 10 seconds. It keeps on doing this in the same cycling pattern.

Lexus looked at it today and re-gassed it as they said there was some air in the system but drove 30 miles after and problem remains. I don't think they have the ability to diagnose. Before I took it to Lexus I got Kwik-Fit to re-gas the system so I am confident that gas is not the problem.

As the compressor engages and does it's job i.e. it cools the air very well, my guess is that it may be a faulty sensor telling the compressor to switch off prematurely. This only a guess as I don't pretend to know about this aspect of cars, although I am somewhat interested in mechanicals in general. Hate cars with sensors all over the place. They can ruin a good car.

Am at a bit of a loss. If Lexus can't help, where else do I go? Changed the AC relay just to eliminate it and it is not faulty.

If anybody can shed some light I would be most grateful.

Regards to all.

I assume by "disengage" you mean the engine revs drop off back to around 600ish then theres a pause before it starts pick up to the revs for when the air con cuts in. There is a sensor actually on the aircon compressor but it would be a bit of a trial and error swap to find the fault as i don't know the aircon circuit.

If you look here theres a few diagrams may give you some clues http://www.toyodiy.com/parts/p_E_1995_LEXU...QFW_8719.2.html

Thanks for the reply, I will try and analyse with help of a friend with a brain. Regards.

Sounds like you got yourself a leak somewhere, the low pressure switch is cutting the power to the compressor clutch to protect it, after a while once the high and low side pressure equalises the switch comes back in and allows operation of the compressor albeit temporarily, NO a/c systems require recharging as a service the refrigerant Never wears out just escapes!

Air in the system??? theyre full of sh*t air in any a/c system is certain death! your system needs pressure testing and a leak test carried out , once you have located the leak and sorted it then you can vac it out and recharge to the correct amount.

Hope this helps,

good luck!

[razagilani]

My series 1 GS300 has a problem with it's AC. It switches on fine but then only runs for 10 seconds before disengaging the compressor. It then stays off for 30-40 seconds and then starts again, but only for the same 10 seconds. It keeps on doing this in the same cycling pattern.

Lexus looked at it today and re-gassed it as they said there was some air in the system but drove 30 miles after and problem remains. I don't think they have the ability to diagnose. Before I took it to Lexus I got Kwik-Fit to re-gas the system so I am confident that gas is not the problem.

As the compressor engages and does it's job i.e. it cools the air very well, my guess is that it may be a faulty sensor telling the compressor to switch off prematurely. This only a guess as I don't pretend to know about this aspect of cars, although I am somewhat interested in mechanicals in general. Hate cars with sensors all over the place. They can ruin a good car.

Am at a bit of a loss. If Lexus can't help, where else do I go? Changed the AC relay just to eliminate it and it is not faulty.

If anybody can shed some light I would be most grateful.

Regards to all.

I assume by "disengage" you mean the engine revs drop off back to around 600ish then theres a pause before it starts pick up to the revs for when the air con cuts in. There is a sensor actually on the aircon compressor but it would be a bit of a trial and error swap to find the fault as i don't know the aircon circuit.

If you look here theres a few diagrams may give you some clues http://www.toyodiy.com/parts/p_E_1995_LEXU...QFW_8719.2.html

Thanks for the reply, I will try and analyse with help of a friend with a brain. Regards.

Sounds like you got yourself a leak somewhere, the low pressure switch is cutting the power to the compressor clutch to protect it, after a while once the high and low side pressure equalises the switch comes back in and allows operation of the compressor albeit temporarily, NO a/c systems require recharging as a service the refrigerant Never wears out just escapes!

Air in the system??? theyre full of sh*t air in any a/c system is certain death! your system needs pressure testing and a leak test carried out , once you have located the leak and sorted it then you can vac it out and recharge to the correct amount.

Hope this helps,

good luck!

Many thanks for your advice, I will proceed along the lines you suggest, regards and will report findings soon.