'93 Ls400 Climate Control Condenser Fans Question

[RCG]

Hello All:

Last week during 90 degree weather, my climate control stopped blowing cold air. I toggled the a/c switch and noticed that when on I did not feel the engine drag I normally feel when the system is working.

Short version is my local mechanic drained, cleaned, added refrigerant and dye to the compressor and now 39 degree air comes out of the dashboard.

BUT...he said neither of the 2 condenser fans operate when the a/c is on. He says they should be on when the a/c is on.

I have owned the car since new and on only a couple of occasions do I ever remember any fan noise, so I am not convinced the fans should be always operating when the a/c is on.

The mechanic is suggesting there could be a switching problem in the dash or then work the way down the wiring to the fans themselves and their controls. He couldn't offer a quote and intimated it could be spendy.

Any one who can offer advice will be appreciated.

Thanks

[RDM]

Both front mounted fans should be on anytime the A/C is switched on. Every car on the road is like that, though some only have one fan. I'd check both relays first, as well as all fuses. Then you can power the fans with a battery directly to test them if you don't find anything else wrong.

[SRK]

Both front mounted fans should be on anytime the A/C is switched on. Every car on the road is like that, though some only have one fan. I'd check both relays first, as well as all fuses. Then you can power the fans with a battery directly to test them if you don't find anything else wrong.

Are you guessing here? Every car? Probably not. Neither my LS nor my GS turn the assist fans on with the AC. Those fans are controlled by the AC system pressure, and only after idling in heavy traffic do they start up. Otherwise the engine driven fan is enough.

[RCG]

Both front mounted fans should be on anytime the A/C is switched on. Every car on the road is like that, though some only have one fan. I'd check both relays first, as well as all fuses. Then you can power the fans with a battery directly to test them if you don't find anything else wrong.

Are you guessing here? Every car? Probably not. Neither my LS nor my GS turn the assist fans on with the AC. Those fans are controlled by the AC system pressure, and only after idling in heavy traffic do they start up. Otherwise the engine driven fan is enough.

Are the condenser fans I refer to the assist fans you refer to? As I said in my post, I very rarely heard a fan come on when driving or idling so I am suspect about them being on all the time the a/c is on. The mechanic said one is a low speed fan and the other a high speed fan and the a/c calls for either or both when on.

I really don't want a mechanic chasing something that doesn't exist. Is there access to Lexus manuals that may discuss this?

Thanks to both of you for responding.

RCG

[SRK]

If you have 39F air coming out of the vents with an ambient temp of 90F, then the AC is working fine. The assist fans do not come on with the AC switched on - the AC is used in any ambient temp - like in rainy weather - by the climate control to dry defrost air for the windshield. The fans come on when needed, and consider too that Lexus avoided unneeded extra noise by doing so.

[RDM]

Both front mounted fans should be on anytime the A/C is switched on. Every car on the road is like that, though some only have one fan. I'd check both relays first, as well as all fuses. Then you can power the fans with a battery directly to test them if you don't find anything else wrong.

Are you guessing here? Every car? Probably not. Neither my LS nor my GS turn the assist fans on with the AC. Those fans are controlled by the AC system pressure, and only after idling in heavy traffic do they start up. Otherwise the engine driven fan is enough.

Why would I reply with a guess? I'm a 14yr Nissan and Toyota technician. I've never seen any model of either one that didn't trip the fans with the A/C engaged. My LS400 turns both on with the A/C.

[Flighing SC]

Both fans on my 93 LS kick in when the a/c is on