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Greeting Honda Enthusiasts, I am a new guy. How goeth?
The purpose of this post is to seek assistance for the purpose of fixing my A/C unit.
I have been trying to fix this for a while but I want to concentrate on the most recent doubt.
It's just a simple question, I read through my service manual for my Honda Civic 2001 EX and one of the tests that I needed do, was checking the resistance on the Evaporator Temperature Sensor. I did not run through the diagnostic mode on the defroster panel, I just kind of jumped into diagnosing the evap sensor since it kind of triggered in my mind, considering my a/c unit does not come on...and while the a/c did work when using a bypass wire to directly power the underhood relay.
Anyway, my question is: When checking for resistance in the evap temp sensor, my multi-meter readings would fluctuate when i bent the wire. So does this mean it is a bad sensor or just a bad wire? Furthermore, could this be the root of my problem? Albeit I do acknowledge I hath not provided enough information on the matter, I just want to square on this one extremity. If that's okay. Thank you, Honda family.
I look forward to sharing Honda Eureka moments with you and if at possible maybe even helping out.
-Mitch
EDIT: So Basically my a/c is not working, it just blows hot air, the heater does work though. I was driving in the rain a few months back and something got shorted I suppose, My a/c was working fine before...Water leaked into the driver's door switch control. That is the only place I know for sure that it leaked. And yeah the door switch does not work. That's all I really know that can help anyone, other than that like I said before, it does cool when bypassed with a wire running directly from the a/c compressor underhood relay box to a power source.
The thermal protector seems to be missing, and my high and low pressure cavities are open, they are missing the caps. Not sure if this is vital but I did notice frost surrounding the pipes when the a/c was working with the caps off.
Also: I replaced the underhood relay box since my radiator fan is not working, and I failed to get voltage from one of the pins on the radiator fan socket (pin 1 or 2) don't remember but when I replaced my old fuse box with my new one I was able to get voltage however my fan still doesn't work because I need to get the radiator fan switch replaced too. I'm just waiting on more funds to come in, so I can fix it. I am also missing an oxygen sensor.
I can't really keep going anymore diagnosing it, until I get that radiator fan working. I think the condensor fan and maybe even compressor is dependent on the radiator fan being powered?
I'm not sure, I took it to a lot of mechanics. thanks for any input.
It's very rare for one of those to go bad. Normally it's the expansion valve that goes bad. That sensor is designed to shut down the compressor when the expansion valve is bad and causes the evaporator to freeze over.
It's very rare for one of those to go bad. Normally it's the expansion valve that goes bad. That sensor is designed to shut down the compressor when the expansion valve is bad and causes the evaporator to freeze over.
so are you saying I have a bad expansion valve?
Let me give you some more input to work with...
My A/c is not working, and I actually had it working through a bypass wire that ran from the a/c compressor relay, condensor fan relay, and radiator fan relay. All those three relays were connected to the blower motor 4 pin connector, and were controlled by the blower motor control, or fan control on the center panel.
the left control in the above picture. my a/c compressor was wired to when I turned it on it came on....My a/c did cool, so that indicates that my compressor is working?
I'm not too sure but can you help me isolate parts that are not my problem? Can I single out the evaporator? I'm sort of convinced it's an electrical problem but I can't really say...I just know that it has something to do with triggering the compressor on, something in between. Let me know...thank you.
by the way I forgot to mention that I did check it for resistance, (the evaporator temperature sensor) in case it was the problem. and I read about 5.7 ohms, so according to this chart below...It is within spec.
Oh and also I just noticed my compressor doesn't have a thermo-protector...so that's a good place to start...
I'm not sure if I did it correctly but I just had the sensor connected to the car, slit the coating on the two wires and alligator clipped it to my multimeter. Had to have the car running to pick up a reading though...it was a steady reading though no spikes or anything.
I also ran the diagnostic mode on the defrost panel and it read 14 blinks while I had the Evap sensor disconnected when I put it in IG2, so I think the panel is mostly working however the lights on the ***** on the heater control panel aren't lighting up so it could be more than one stone required to break this goose's neck, if you get my gist.
you still have yet to state in detail what was happening before you started modifying the wiring, that's crucial to help diagnose the issues, just because you're testing the evap sensor doesn't mean I or anyone can accurately tell you what the problem is
your compressor should have a thermal protector, even if it's an aftermarket
If something shorted then it's likely an electrical problem not a mechanical problem. I would suggest finding someone good with electrical work and having them trouble shoot it. First, check the fuses in the driver side kickboard panel. Could be as simple as a blown fuse. Put everything else back the way it was. It's really not wise to bypass things.
Anyway, check yelp for someone good with electrical work in your area with good reviews.
If something shorted then it's likely an electrical problem not a mechanical problem. I would suggest finding someone good with electrical work and having them trouble shoot it. First, check the fuses in the driver side kickboard panel. Could be as simple as a blown fuse. Put everything else back the way it was. It's really not wise to bypass things.
Anyway, check yelp for someone good with electrical work in your area with good reviews.
Maybe in another life I would attempt to seek professional help, however in my current state I don't have the funds available.
Good advice, but do you suppose you can give me instructions on how to remove the a/c thermal protector located on the compressor at least. I really could use a bone.
the thing is I've taken it to lots of incompetent mechanics and that's probably why the thermal protector is missing, I didn't even know about it until I read through the service manual. I just would really like to know a description of "how to" remove/install or be given a video to guide me on how to install it. I'm not a professional but I am mechanically inclined. Any input would be appreciated.
Sounds like you have a short. I would pop that sensor out and check the connectors where the wire goes. They do wear out and loosing up sometimes. Or the wire is shorted somewhere. You shouldnt have a change in resistance just by moving the wire. That sounds very much like a short to me. But i haven't messed with ac that much in cars(or anything) so my knowledge is limited in that area.
Sounds like you have a short. I would pop that sensor out and check the connectors where the wire goes. They do wear out and loosing up sometimes. Or the wire is shorted somewhere. You shouldnt have a change in resistance just by moving the wire. That sounds very much like a short to me. But i haven't messed with ac that much in cars(or anything) so my knowledge is limited in that area.
I was checking resistance on it while it was not attached to the car. Just as a stand alone, that's when I would bend the wire and get varying resistance readings. Then I plugged the Evap sensor back into it's socket, turned the car on and was able to read about 5 ohms of resistance, I'm not sure if I have a good sensor or bad one to be honest. The service manual states that the resistance test is to be done while the Evap Sensor is unplugged and if I read anything out of spec then I should replace it. Thanks a lot for the help!
Originally Posted by holmesnmanny
it's a simple bolt on assembly, you don't even have to evacuate the system but you will be doing it for nothing
do some searches and find out how often those fail
That's all good and great but you must have misread my post above where I stated "I'm missing the thermal protector" I don't even know what to go by as for as installing it properly. There's nothing attached on top of the compressor where the bolts are, like I've seen in the pictures online. So I would need to figure out exactly how one goes about installing one of these...
My blower motor fan is working...Correct me if I'm wrong isn't that it's (power transistor) purpose?
Fan works great if you're into having hot air blown in your face...
Nah', I get enough hot air in my face from my boss...
But, I was more referring to the information further down in the thread. That thread seemed to spark a bunch of side-conversations regarding HVAC, is all.
Nah', I get enough hot air in my face from my boss...
But, I was more referring to the information further down in the thread. That thread seemed to spark a bunch of side-conversations regarding HVAC, is all.
yeah well, I read through it and the only thing that might have helped me was that diagnostic mode, where you hold the circulator button and defrost button while you turn on the car. I tried that already, and I don't get any blinks...so there's something else going on, I tried jumping the a/c clutch at the under hood relay box and it did, I had it cooling through a bypass.
Oh and I forgot to mention the control panel where all my hvac ***** are might be shorted or something, because some of the lights on there are not turning on anymore, the light bulb for the fan speed **** doesn't light and the one for the a/c temperature mixture doesn't work either. Those lights stopped working after a mechanic tried diagnosing my a/c, he was unable to fix it. I feel like when he was using the power probe to check the wires he might have shorted something out and burnt the bulbs...He did a lot of testing.
It might just be the bulbs...but I was unable to test the control panel with the mulitmeter, when I unplugged the control panel...It's kinda of hard to diagnose since I guess I have to have the car on and running to pick up a reading. I guess I would have to pull out the radio and then maybe just have it hanging with just the cp (no radio) while I probe. All that weight on the wires is not good I know. What I need are extensions to those connectors to be able to set it on the passengers seat while I probe. I don't know if that exists...
08-20-2017, 01:34 PM
Evaporator Temperature Sensor
