A/C Questions

Could a botched relay wiring also cause the ac button not to light up? I already switched bulb but it sill won't light up. Is this directly related to my compressor issue sine it may be part of the circuit?

 

wtf! what kind of wiring is this?

In hope to trace the root cause of why my ac compressor is always on, i opened up the fuse box and looked into the wiring... This is what i found... Theres like at least 4 lines that are daisy chained (tapped) and i don't know if this is normal... Being wrapped in electrical tape, my bet is someone rewired stuff in the car... Any suggestions on where or how to start "normalizing" the wiring?

 

I couldnt really tell where the 4th wire is, or the line was totally cut... There is one wire from the compressor clutch relay that is connected to another relay and both wire are traced to be connected on fuse number 17 on the main fuse box (fuse box 1). By the color of the wire it looks like it is a ground wire but im not certain. I hate electricals specially if im ignorant in it!

BTW, my piano wire that controls the water valve also broke when i was trying un-seize it yesterday... in a desperation search, i found this... http://www.toyotapartsoverstock.com/p/__/CABLE-SUB-ASSY--WATER-VALVE-CONTROL/4126492/8728620070.html and http://www.villagetoyotaparts.com/p...--WATER-VALVE-CONTROL/2392708/8728620070.html

i will call the local dealer and see if they can get this for me to save on shipping...

 

so much for keeping my hopes up but the part is no longer carried.. duh.... maybe can try those universal control cables and just cut it to length to match the stock one...

also, anybody know how I can gain access to that servo motor so I can replace the that wire/cable?

 

Trying to replace my heater valve cable but...

Finally got it done!!! The universal control cable you can buy at your local auto store works fine... Now I have regained my heat/cold function with the slider...

here's some pics:


Only problem no is that my A/C Compressor won't turn on now... If you recall, my initial problem was that the compressor was always on when i turn on the blower fan... now, it is totally gone... it won't engage at all... the only the way it engages is when i short the clutch line directly to a 12 source.

here's what i did today with the a/c...

1. fixed piano wire
2. tested a/c amplifier - since not all the test value was correct when i did the test, i am assuming my a/c amplifier is working?
3. tested hvac swtiches/control - confirmed that there is circuit continuity
4. tested hi pressure switch - yielded zero ohms when wire lead was tested
5. tested ac clutch relay - this i am not sure about
6. traced some wiring specifically the a/c switch line to the a/c compressor relay box
of all the things i did, i do not have any clue what disturbed the ac magnetic clutch line... i do know however, that my hvac controls, high pressure switch are working as per the test... as for the ac amplifier, im guessing that it is working fine since according to the test diagram, not all tests that i did was according to the specified readings...

on the relay box, when i tested the line with a multimeter, i connected the violet/red line to the blue/yellow line, which if i read the diagram correctly, should be connected to the a/c switch passing through the a/c amplifier... when i pressed on the a/c switch, i did get a reading from my multimeter, and none if i de-press it... which leads me to believe that the line is ok and there is continuity...

based on my assumption is that this could be a relay problem or maybe i am low on charge... thoughts?

 

Not relay. Used a working one and compressor is not kicking in.

 

Finally!!! The a/c button is now fixed!!!

After two hours of tracing the a/c line, it was just a simple fix after all!! There was a broken circuit in the a/c amplifier board that I just needed to re-solder... after spending time and energy, this was the last ditch effort in calling it quits... and voila!!! my a/c button is now working and turning on/off the compressor!!! Now I have the ability to turn the freakin compressor off when not in use! haaay... if I caught this broken circuit when I removed the amplifier before I traced the a/c line, I could have finished the whole job in 20 minutes! anyway, it was a good learning experience and gave me some insights on how to read and follow the wiring diagrams...

anyway, despite fixing the a/c button, I still have some minor things to fix... namely:

1. A/C button light still not lighting up when pressed in... BTW, what type of bulb does the hvac control use???
2. Need to recharge since air is not getting any cold
3. Replace blower resistor and hope that it would fix my auto fan feature and Lo fan blower setting (anyone has a spare?)

 

Passenger side.. if you look underneath and behind your glove box, you will see the A/C cooling unit... if you are looking straight up from underneath, there will be a cover with one screw housing the amplifier board on the left side. It is hard to miss since there will be a harness connected to it... one screw is the only thing needed to get it off, plus ofcourse unplugging the harness...

 

Compressor cycle

So now that I got my a/c button to work, I noticed that my compressor does not cycle on/off while a/c is in use... I know some cars with the manual controls, the compressor should cycle when the temp is reached to prevent the line from freezing... now if my car has the auto temp/climate, should the compressor also cycle on/off, or constantly stay on?

also, what is the difference between the thermistor and the expansion valve?

 

http://i228.photobucket.com/albums/ee111/st165-2765/dirty deeds/043013c.jpg

it states on the last part of the manual that the clutch should continuously be energized provided all conditions are met... does this mean that the A/C compressor should not be cycling on/off like other cars?

 

wait... im confused... yes, all conditions are met, so should it cycle on/off, YES or No?

thanks!

 

thanks... i did a retro from r12 to r134 when I was tinkering with the AC... since I do not have the right a/c manifold gauge, I need to re-check the actual pressure reading and see if low freon is the culprit... for me it blows cold enough, but maybe at the expense of it not cycling through... however, i read somewhere that some vehicles (not specific to 4th gen Celica's but some Ford and GM's) that has the auto climate feature, their compressor is always running when the a/c button is pressed so it made me think...

I also tested the VSV by the firewall if it was working and found out that it is not... is this the correct VSV for the a/c idle up? maybe this is the reason why my idle drops when the compressor kicks in...