gtstcactus

Hey

I'm trying to get my air con working in my 92 Windom/ES300....

The A/C control panel works - I can dial a temperature, I can select front defog, rear defog, I can choose the various different blower settings - blow on face, blow face and feet, feet only, feet and defog etc. I can select fresh air or recycled air. The clock in the a/c unit works. I can select the auto function. I can turn the a/c off but still select functions etc.... When I choose to have the air blow differently I can here the bits and pieces (actuators???) whirring and shifting etc doing there thing I think as they should. The only problem is I dont get ANY air blowing - hot or cold... My system blows no air whatsoever air con or or on it doesn't matter...

I've run the diagnostics and the 2 codes I got were 21 which was for the solar sensor (I've got to re-run diagnostics whilst in direct sun to check this). The other code I got was 23, I forget what this means but I think it was to do with a pressure sensor or switch perhaps...???

I pulled the blower motor out yesterday and discovered what looked like a birds nest in it, tho it was likely just straw and hay etc... I thought for sure that would have been the cause - likely having burnt out the blower motor... However I hooked the motor up to my battery today and away it went spinning freely..... So apparently it's not the blower motor which means I need to work out why it's not blowing any air, given it works....

I'll reconnect it and see if it works with all the birds nest removed from it but I suspect that isn't going to work, the problem must be somewhere else... presumably somewhere between the blower motor and the air con control unit???? Is that a fair assumption??

so how do i check the relay?? i have a basic multimeter now... is the air con ECU part of the control unit?? how do i check if that is the problem??

is a multimeter any use in diagnosing thiss???

How do I remove the A/C relay thing in the fuse box under the hood??? I've got a couple of spares from the wreckers but I removed them by just breaking them out wrecking the fuse box.... I'd prefer to keep mine intact!

nwa320drvr

Since you found that the blower was operating I would check to find out if power is being supplied to the blower when selected on. If you are getting power to the blower it could be that the blower motor resistor is bad. The resistor allows the blower motor to spin at different speeds as required by the controller.

Good lucking on finding the cause.

George

gtstcactus

Thanks George, that seems like the logical next step to take....

I'm a complete novice when it comes to diagnosing electrical problems, how / what would I do with the multimeter to determine if power if being supplied to the blower???

Also how do I test the relay out?

nwa320drvr

I assume you checked the fuses first. Start easy and work your way up. I'm not an electrical whiz either, but here is what I would do.

I would set the multimeter to DC Volts on the 15 volt scale (if that's selectable) and check for voltage to the blower motor when it's selected to the on position on the HVAC controller. It would be nice to have a wiring diagram to know which pins to check on the connector, but I think there are only 2 so it should be fairly easy. If the blower is selected on and you are getting power to the connector to the blower motor that eliminates the controller and wiring as a possible fault.

Checking the relay would be a little tougher without a wiring diagram to know what's supposed to happen. Swapping out the relay with the same type would be easier.

Here's a link to a thread on the SC 300/400 on club lexus that might help out. Search around and you'll probably find more info.

https://www.clublexus.com/forums/sc-...n-speed-2.html

Looks like there might be two parts, a blower motor resistor and a transistor if yours is the same as the SC. Having a manual would be a big help. You can get a two day subscription to Toyota's Technical Information System (TIS) for $15 and download all the manuals and other info. It won't be on paper unless you print it, but you would have it available.

https://techinfo.toyota.com

Good luck. I hope you get it fixed.

George

gtstcactus

I've been watching lots of videos on youtube on multimeters and diagnosing car troubles....

Does someone have a photo of the heater relay in the car??? I think I understand how to test it properly both the switch and the rest of it...

I found some wiring diagrams in the FSM, they can be a little confusing tho....

I've checked the fuses I know about tho I think there may be some 1 or 2 near the heater relay which is near the blower motor is I understand right...

Also need to check the a/c relay under the hood....


Relays I need to check with power from 12v battery and then also check for continuity to see if it's putting out as well as taking in...

I guess I need to check for voltage / current in the connectors for the blower motor...

I think the wiring diagrams tell me a few things to try, the battle is locating the connectors,m relays and whatever!

gtstcactus

Ok, I've spent the last few hours in the dark too... trying to diagnose the problem with the a/c or even better get it working.... I am so damn frustrated I could scream!!!!!!!!!!

So lets review what I've tried.... not in order...

1. checked all fuses - fuses good
2. rem ove blower motor and test with power direct from battery - blower motor works!
3. tested the voltage at the blower motor plug - got about 12v.... I presume that means the plug can power the blower...
4. tested heater relay - checked magnetic switch operation, and continuity of appropriate terminals... it's good... I can also hear it working when the blower is turned on,,,
5. also measured voltage between terminal HR of air con control assembly (a/c ecu) and body ground voltage correct.
6. checked voltage between terminals IG+ and E of a/c ecu - correct
7, checked voltage between terminal acc of a/c ecu and body ground - good
8. I pulled the A/C magnetic relay from relay box under the hood.... it appeared to work and have continuity, but I don't think the switch was engaging,,,, If I took my pliers i could close the switch (I think that completes a cicuit) and it would make a noise somewhere near where I think the compressor is....
9. I had a couple of spare A/C relays so I swapped them to see if there was any difference but it's the same with them all.... it seems the switch stays open when installed in the relay box... -IS THIS SIGNIFICANT???
10. I had the blower motor connected to it's power plug and hanging / sitting on the car floor...
I turned the air con on (blower on) with ignition to on, but car not running... nothing, I turned the ignition and the blower started working!!!!!!!

So i thought I've won problem sorted, put the blower motor back in it's place, put everything else back together. Try out the air con and the blower motor does nothing.... still no frickin air blowing out of the piece of crap **** fuc#$#$% thing....

So my question is could the compressor stop the blower from blowing air???

What exactly does the A/c relay in the relay box under the hood do??? does it matter if the switch doesn;t close (like when you power a relay)?????

The fuse by the heater relay looked ok and has continuity....

I was unable to investigate the compressor at all as it was too dark...

I don;t understand why the blower motor would work suddenly and unexpectedly when I had the blower on and turned the ignition on, and then it don't work anymore when I put everything back together...??????????????

Help please!!!!!!!!!!!!! I can't take much more, I fell like making a sledge hammer my next tool in dealing with the problem....
Where do I look next??? I'm so damn pissed off and angry and I can't take much more of this....
I really can't afford to pay someone to fix it, I want my air con working this is really starting to aggravate me.....................

nwa320drvr

Sorry to see that you didn't get it sorted out yet. I know it can be frustrating....

As far as I know, the blower motor should operate independently of the operation of the a/c compressor. In other words, if you select the a/c on, the blower should operate even if the compressor is not functioning correctly. The air would not be cooled, but it still should blow air. At least that's how its been for all the cars I have owned (including the one with the broken a/c clutch) but Lexus could be different.

George

gtstcactus

Ok I pulled the blower motor out again this morning - it was getting voltage at the plug connector.... blower spins when connected direct to battery,,, but it won't spin when connect to it's plug.

I had it unbolted but still connected and turned it on nothing happened.... I gave it a spin for some reason and BINGO it starts spinning away freely I inserted it into it's housing and I'm getting air throughout the system.... Hot and cold air!!! This was running the fan at full speed...

I turn it down a notch to medium and it stops working,... I try the low setting and no joy there nothing happens...

So back to high and nothing, I spin it and it goes just fine.... If I turn it down while it's going it stops working but if I turn it back to high it will continue if it was still spinning....

So would this be the resistor???? I think george said the resistor controls the different speeds etc....

So why won't it spin on it's own like when connected direct to the battery????? Why do I have to spin it to start it working???

Will replacing the blower motor be the answer to this one??? Is the resistor part of the blower motor or does it live somewhere else??????? I feel I'm close to solving this one but I don't want to count my chickens too soon....

So shall I head to pick a part and get a blower motor from one of the Windoms or ES300s???

gtstcactus

Well I just pulled the blower motor to bits out of curiosity and it is now destroyed... lol

So I'll grab a replacement blower motor from pick a part tomorrow perhaps....

PFB

From the symptoms you described the problem was not a resistor, but the blower itself. So getting a new/used blower was the only option.

gtstcactus

Well that's a relief and I really hope so! As if it is not the blower motor I'll be feeling like a right dork for destroying it....

Was interesting to have a look at the insides of it, was a bit of corrosion in there not major but very noticeable......

On the off chance the blower motor is not the problem can someone tell me where the blower motor resistor is on a 1992 ES300???

So the symptoms of the blower only starting with a push / spin from me, & the fact it only ran on high speed indicate the blower motor as the faulty item???

I thought I'd read if your blower only works on one speed it's the resistor...??? However those cases didn't seem to have the added factor of having the physically push the rotor to get it going..

There is 2 Windoms, 1 ES300, and a couple of VCV10 Camrysat the local pick a part... So I to hope one of them has a working blower motor!

What tests can I do on the motor while I'm at pick a part?? I can't actually run it as you can't turn the cars power on... There aren't any batteries in the cars and you can't take on in...
I might be able to plug it into one of the batteries for sale quickly to see if it spins... but as I've discovered that does not guarantee a working motor! I guess I will take my multimeter and see if I can get any useful diagnosis before I purchase one... I really hope I'm successful, I hate not having the heater working, and no A/C is a pain sometimes too!'

nwa320drvr

Glad to see that you're finally getting it narrowed down. With the symptoms you described it does sound like the motor was one of the problems. Only running in high speed and nothing else still points to a bad resistor. You might want to pick up a spare at the yard just in case. When you pull the blower off the wreck, cut the wires on the other side of the connector leaving enough slack to connect it to one of their used batteries. Bring along your cutters, remove the insulation and test it on one of their batteries. They won't take it back if it doesn't work later, so they should let you do that.

I've attached a page from the parts catalog off the web. #87138 is the resistor. There is also a transistor assembly #88750A. I don't know what that does. I hope that helps you locate it on the housing.

George

gtstcactus

Thanks for the diagrams George......

I wish I'd seen your post before I'd gone to the wreckers! Not to worry tho...

I grabbed the blower motor out of a 1995 ES300 figuring it might be a better choice than one of the 1992 model Windoms... I took some alligator clips along with me to test it on one of their batteries and it seemed to spin just fine...

On the way back home I had a thought..... My old and now destroyed blower motor also spun just fine when connected to the battery...... So why is it that it would spin when connected direct to the power source without me having to give it push start????? Clearly it was capable of starting spinning without help from me....

So I'm thinking I'm probably going to run into the same problem when I connect the new motor...
I could be wrong but that's my current line of thinking - I could easily be wrong given my limited understanding of electrical systems etc...

I quite like going out to pick a part so I'll probably be back out there this week so I'll have a hunt for the resistor when I'm there...

I also grabbed the cabin filter out of the 95 ES300, it was a bit dusty but in good nick, nothing a vacuum cleaner and air blower gun can't fix... There was only one filter in there, tho it's designed to fold at the middle... I thought there is supposed to be 2 filters one you push upwards and one to slot in underneath it...???

gtstcactus

Morning folks.......


Just went down and installed the blower motor........

We have partial success.....

It works on full power setting only..... Nothing on medium & low....

So I guess that means the resistor..... I see where it is on the diagram but I'm not certain where the stuff in the diagram is in the car! I'm guessing it's in the centre behind / underneath the a/c & radio perhaps...????

Looking at the FSM diagnostic chart I'm thinking it looks like either the "power transisitor circuit" or the extra high relay circuit.......

The FSM suggests those as the 2nd and 3rd option to check when you have "no blower control"

I'm pleased I've got some use of the heater / air con tho, very pleased!

Still more work to be done tho...

gtstcactus

Could someone point in me in the general direction of this dastardly resistor responsible for one one speed heater / air con system???