Problem With My Air-conditioning? Lexus Es-300?

Linux2 · September 4, 2008

:o As I was driving yesterday, the A/C on my 1998 Lexus ES-300 stopped blowing cold air. The green light above the A/C button, which is normally illuminated when the A/C power is on, began to blink. Now, whenever I turn on the A/C, the light blinks and it just blows hot air. I took it in thinking it just needed freon, but they told me it had freon so that wasn't the problem. Does anyone have any idea what could be wrong?

blk_on_blk · September 4, 2008

Yep... and you aren't going to like the possiblities. First off is the most minor, and that's that the relay has gone bad. If you search on this and other toyota/lexus forums, you'll find this is a very common problem... plus you'll find the right replacement number. I think it's about a $50 part.

If it's not the relay, then what you had happen is probably the same thing that happened to us, and that's a clog in the system. Usually it means there is enough wear-n-tear on the compressor that fragments of it have come apart and clogged somewhere in the system (often the expansion valve). We had to have the compressor, drier, expansion valve, and a few other parts replaced. I sourced all the parts and paid a local shop to do the work. all in all, it was ~$1300 out the door blowin' cold again. You need an experienced shop to really tell you if you have a block somewhere in the system (they can check pressures on the high and low side of the system).

mrbutz1 · September 5, 2008

Yep... and you aren't going to like the possiblities. First off is the most minor, and that's that the relay has gone bad. If you search on this and other toyota/lexus forums, you'll find this is a very common problem... plus you'll find the right replacement number. I think it's about a $50 part.
If it's not the relay, then what you had happen is probably the same thing that happened to us, and that's a clog in the system. Usually it means there is enough wear-n-tear on the compressor that fragments of it have come apart and clogged somewhere in the system (often the expansion valve). We had to have the compressor, drier, expansion valve, and a few other parts replaced. I sourced all the parts and paid a local shop to do the work. all in all, it was ~$1300 out the door blowin' cold again. You need an experienced shop to really tell you if you have a block somewhere in the system (they can check pressures on the high and low side of the system).

Whoa, almost my exact question. Very rainy and humid day in Chicago yesterday and my defrost was nonexistent. I mean NO removal of condensation from the windshield or side windows. My AC was recharged last summer (15 months ago) and did not work this summer, but the AC light comes on and stays on, but I don't notice a change in the vibration or hum of the engine (nor any appreciable movement on the tach) when I press on and off.

Bad compressor? Car is undrivable in any weather that produces condensation in this state. But $1,300? No way the wife will put up with that for a 14 year old car!

Thoughts and advice appreciated.

blk_on_blk · September 5, 2008

On ours, we could feel the compressor engage when we would turn on the A/C, but it just wouldn't blow cold. If you aren't feeling any kind of change when turning on the A/C, I would look first at the relay... but in most cases the relay will trigger the A/C indicator light to flash. Here's a link with some more info: http://www.toyotanation.com/forum/showthre...elay&page=2

It could also be that your cabin filter is dirty/clogged. When there is too much restriction in the fliter system, apparently the A/C will lock out. It's worth checking.

Linux2 · September 6, 2008

The cabbin filter as well as coolant have been changed quite recently and it has nothing to do with the compressor cause I hear it when it works.

blk_on_blk · September 8, 2008

Hearing the compressor engage and load doesn't necessarily indicate it's functioning properly... or it could be functioning properly and theres a blockage elsewhere in the system. It's hard to say. At this point, you'll need a talented A/C guy to monitor the system with pressure gauges as the system engages, loads, and cycles.

I don't know how "smart" the flashing light is on the A/C button, but if it's flashing, then the system is picking up there is a problem. I'm not sure if our A/C light was flashing or not when our A/C went out, so I don't know if the system will pick up a blockage as being a problem or not (don't know what triggers the flashing light).

If your system is fully loaded with refrigerant, and your compressor is working correctly, then I'd be looking at the expansion valve as the next viable culprit. Again, a talented A/C guy could tell you more precisely.

lexusrob · April 5, 2009

None of the relays are labeled in the fuse box cover or in the owners manual. How do I tell which one is the a/c compressor relay? 2003 es300

capnfred · April 6, 2009

The flashing light indicates that the AC ECU has stored a fault, enter into the diagnostics and see what the system thinks is wrong with it.... if you don't have an FSM (factory service manual), (and if your going to do your own maintenance you should have one.) The next best thing is alldata... this is an online service, some public libraries have access to this....once you know the fault code you can troubleshoot the system..... I don't know about your series, mine is an 93, but all the controls for the climate control system are under the dash... as for the tach indicating that the compressor is running, well the fine Toyota engineers have the engine control system compensate for the added load and if all is running well the engine should not change speed when the compressor engages...at least mine does not....there are many sensors that the climate control ecu uses to determine if the compressor clutch is engaged or not, and it could be any of them.... so bottom line is that if the run of the mill AC tech works on your car he may end up mis-diagnosing the problem, or could even damage your system..... the Toyota AC system has a few quirks that are unique to them.... and they could mislead the uninformed..... so be careful who you let work on your car, this does not neccesarily mean that your only choice is the dealer, it just means that the technician that you choose should be intimately experienced with computer controlled AC systems.....so enough said,,, good luck.... hope its not a major problem.

capn

homemechanic · April 6, 2009

if you don't want to spend major $$$ to fix the AC, try some anti-fog solution or FogX solution on the interior windows. You can buy that at the auto store. Wipe a thin layer on the glass, and the fogging up problem goes away. The glass wouldn't even fog up w/your mouth blowing on the windows. The down side is you have to re-apply every 2 weeks or so.

Lucky13 · April 6, 2009

No real reason to go OEM though. Aftermarket is much cheaper as you will probably need a new compressor.

Rong · April 18, 2009

My 1997 ES300's A/C light also keep flashing three weeks ago. I went to a shop and the guy checked the whole A/C system and finally he told me the problem lies in the A/C control module which is just below the CD display LCD. He asked for $250 for this part and $150 for labor. I think it cost too much so I went to ebay and found a same control module which was taken from a 1998 ES300 and ask for $50. I bought this module and replaced the one in my car and then the A/C works! So maybe you can have a check of this module too.

But the air blowed out is not cold enough. I checked the pressure at the low pressure port and it seems high enough. I do not know how to get the air colder. any suggestions?

Hearing the compressor engage and load doesn't necessarily indicate it's functioning properly... or it could be functioning properly and theres a blockage elsewhere in the system. It's hard to say. At this point, you'll need a talented A/C guy to monitor the system with pressure gauges as the system engages, loads, and cycles.
I don't know how "smart" the flashing light is on the A/C button, but if it's flashing, then the system is picking up there is a problem. I'm not sure if our A/C light was flashing or not when our A/C went out, so I don't know if the system will pick up a blockage as being a problem or not (don't know what triggers the flashing light).

If your system is fully loaded with refrigerant, and your compressor is working correctly, then I'd be looking at the expansion valve as the next viable culprit. Again, a talented A/C guy could tell you more precisely.