Ac Cooler Fans Arent Working

[jim72]

I had a reman compressor installed , which works, but mechanic couldnt figure out why ac cooling fans dont operate,so prevent over heating , I dont use ac, until fans are operable, any speculation why fans dont operate?

[RFeldes]

Mine don't come on until the car reaches a certain temperature. I assume you are talking about the fans in front of the Radiator/condensor.

[VMF]

i have only 1 fan and ive never seen it working even during the hottest days and my car never overheated. there is a sensor that connects to the radiator you might have it checked in case you want to, but AC and engine have separate radiators and they are not connected in any way, so your car will neveroverheat coz of the AC

[SKperformance]

the year?

[Kennyr]

I had a reman compressor installed , which works, but mechanic couldnt figure out why ac cooling fans dont operate,so prevent over heating , I dont use ac, until fans are operable, any speculation why fans dont operate?

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My fans almost never come on also. I have replaced the fan sensor in the rad but that didn't change anything. My 91 has never gotten hot ever, even at 115 degrees on several trips to Vegas. I have removed my rad and cleaned out the debris from the fins at the time of my t belt job. A Lexus tech I have buddied up to told me these cars never overheat unless you blow a hose, stick a thermostat or run her low on coolent with a leaking water pump. He says the rad capacity is huge and the electric rad fans are just there for the ride since the temp never gets hot enough to turn them on.

[monarch]

The two electric fans are AC condenser fans, not radiatpr fans. Mine sometimes come on when I have the AC on. These fans help remove heat from the refrigerant that's circulating around through inside the AC condenser

[95LS400Bob]

i have only 1 fan and ive never seen it working even during the hottest days and my car never overheated. there is a sensor that connects to the radiator you might have it checked in case you want to, but AC and engine have separate radiators and they are not connected in any way, so your car will neveroverheat coz of the AC

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Ditto for me. Never seen my 95 come on either. I worried about that and so one day I went in there and checked everything there was to check. Bypassed the temp sensor in the radiator and the fan came on. Then I even removed the sensor from the radiator and warmed it up with a propane torch...and the fan once again came on. So....I know mine works..guess it is never needed.

[flanker271]

Everytime I start my 92 the two condenser fans turn on then immediately shuts off. At least I know that both of them works, but like everybody else mentioned here, my fans never turn on even in 105F weather in the Arizona desert during summer.

[jim72]

Mine don't come on until the car reaches a certain temperature. I assume you are talking about the fans in front of the Radiator/condensor.

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[jim72]

Mine don't come on until the car reaches a certain temperature. I assume you are talking about the fans in front of the Radiator/condensor.

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Yes ,I'm talking about the two fans in front of radiator , my non-lexus mechanic

is afraid that ac lines will over heat, not the engine, how long is the delay before the kick

fans kick on?

[RFeldes]

The fans usually kick in when it is very hot and you are "low" on freon as the condensor will heat up.I believe, Later models went to a single fan. The radiator fan seems to be enough to keep the condensor cool during normal driving if the freon level is normal. I suspect it would be for harsh conditions such as stop and go or places like the desert :D I've only seen mine come on once and that was when I was low on Freon. Seriously, the Lexus Engineers really covered all the bases and this is an example of over engineering on our behalf. Relax and enjoy the ride.

[Kennyr]

The fans usually kick in when it is very hot and you are "low" on freon as the condensor will heat up.I believe, Later models went to a single fan. The radiator fan seems to be enough to keep the condensor cool during normal driving if the freon level is normal. I suspect it would be for harsh conditions such as stop and go or places like the desert :D I've only seen mine come on once and that was when I was low on Freon. Seriously, the Lexus Engineers really covered all the bases and this is an example of over engineering on our behalf. Relax and enjoy the ride.

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I worked on Volvos at a dealer for 25 years and they never made a rad. that had 1 drop of extra capacity. Any debris in the fins or the tank and the cars would overheat. Maybe they just planned on selling lots of rads when the cars went out of warrenty. It sure worked at 500 a pop installed.

[Shadow]

...but AC and engine have separate radiators and they are not connected in any way, so your car will neveroverheat coz of the AC.

Not true!

AC condenser sits in front of radiator. Heat given off by the condenser will decrease cooling efficiency of radiator. The net result is decrease cooling capacity of radiator which could result in engine overheating under certain conditions. Over notice signs to turn off AC when going uphill?

[monarch]

AC condenser sits in front of radiator.  Heat given off by the condenser will decrease cooling efficiency of radiator.  The net result is decrease cooling capacity of radiator which could result in engine overheating under certain conditions.  Over notice signs to turn off AC when going uphill?

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Yes, but if hot air blows through the radiator the thermostatically controlled fan clutch will make the engine's fan will turn faster, to help offset the extra heat generated by the AC condenser.

Toyota has used this design on virtually all its rear wheel drive vehicles for more than 30 years.

Only the LS, to my knowledge, has fans in front of the AC condenser and my guess is the real purpose of the fans is to assure excellent AC cooling performance (35 - 40 degree F air from the dash outlets) in congested bumper to bumper traffic during hot weather.

[Shadow]

Toyota Supra turbo also has electronic fan in front of AC condenser to increase heat dissipating capacity of both AC condenser and radiator. LS has excellent radiator heat dissipating capacity when cooling and drivetrain systems are properly maintained and in good working order. In those that are not, even fully engaged fan clutch and electrical fans will not be sufficient to remove buildup heat from radiator, resulting in overheated engines.

[Andrew]

I have a 1991 LS400. According to the shop manual, there are three relays for the (2) fans on the condensor...Relay 1, 2, and 3. One fan is for temperatures above 192 degree and the other fan is for the A/C system. It's a two speed fan: low for below 192 degrees and high for above. When the A/C system is on there should always be a fan on otherwise the high side of the system will not cool off. If the fans aren't working you may a couple of problems. One is the coolant sensor (electrical connection)...unplug it and one fan should come on. Two, one of your relays could be bad. Or three, a fan could be faulty. I've verified through electronics schematics at the back of the manual.

Good luck guys.

[dole2000]

my fans come on whenever the AC is on. Seems a little loud to my ear.

Had a new compressor put in a year ago and been that way since.

[RFeldes]

Sounds like whoever replaced the compressor hard wired the fans not knowing how they really work!!

[XL2007]

I'm glad I found this, because I'm having problems with the condenser fans after a recent starter replacement. In the process of replacing the starter, a blue-colored valve of some sort that sat on a main coolant line crumbled apart, necessitating it's replacement.

A new one is in it's place, but it's not helping me solve the problem of the A/C working half-heartedly. The blowers are just fine, but the A/C is putting out some rather tepid temps. The Freon levels seem to be fine, though, but there's no power going to the condenser fans (huh???)

I've checked the fuses and whatever electrical connections I could find. Now it's time to check the relays....