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AC Compressor and condenser fan ONLY come on when relays are jumped
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flipstyle
User
Jul 14, 2022, 6:45 PM
Post #1 of 35
(4098 views)
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AC Compressor and condenser fan ONLY come on when relays are jumped
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Vehicle: 1997 Acura CL 3.0 v6 Here's the issue: - AC activated from inside the cabin engages the dashboard fans--> nothing but hot air comes out - neither condenser fan nor ac clutch activate when AC is turned on - jumped pins 3 and 5 (bronze contacts) on the relay inputs https://imgur.com/a/VbOYI3n and both condenser fan and ac clutch instantly engage and stay on - measured the pressure on the low side when both were manually engaged and it was low (around 18psi). Filled with proper refrigerant back to correct levels. AC blows cold inside the cabin - Tried testing both relays by applying 12v and ground to the silver pins. I heard audible clicking, but unsure if that's all I need to do - Multimeter was reading 12v on pins 3 and 5 of both relays with the car turned off and ac turned off. Should these leads always be live? I believe maybe so, as all the relay does is bridge this gap - I'm entertaining the notion that both relays might be bad, but the odds of both going out should be fairly slim? - I'm not completely ruling out the possibility of the PCM/ECU unit being bad, as this seems to be common in older hondas/acuras. could also explain the erratic behavior of my radiatior fan. Does anyone have a pin out diagram for my vehicle so I can troubleshoot? - Could the ac pressure switch(es) be a culprit here? And is jumping each one the proper way to troubleshoot? Or is there something I can do on the switch itself with a multimeter? Thanks!
(This post was edited by flipstyle on Jul 14, 2022, 6:49 PM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 15, 2022, 3:02 AM
Post #2 of 35
(4075 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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Quit jumping things like that! AYOR and IMO you'll cause a problem you didn't have. It's old now (I can relate to that :-) so go easy. Boosting up a system is and was not the best nor easy to do. This should have a capacity of 26oz 134a the approach to this by age still would be the same. Vacuum out and charge correct amount no additives and then have a baseline to work from. In that you touched refrigerant now unknowns added I'd suggest going back to knowns not this way, T
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Hammer Time
Ultimate Carjunky
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Jul 15, 2022, 4:05 AM
Post #3 of 35
(4066 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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The PCM controls that relay by applying ground to the trigger only when it is completely satisfied with all the various inputs that it monitors like AC pressure switches, coolant temp, AC request from control head, etc. The Control head looks at it's own inputs like the temp sensor in the evap. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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flipstyle
User
Jul 15, 2022, 5:25 AM
Post #5 of 35
(4058 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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The PCM controls that relay by applying ground to the trigger only when it is completely satisfied with all the various inputs that it monitors like AC pressure switches, coolant temp, AC request from control head, etc. The Control head looks at it's own inputs like the temp sensor in the evap. Thank you so much for the diagram, Hammer! Really, really appreciate it. I'm going to try and fiddle and see if I can identify the wires and triggers myself. However, looking on Ebay it seems PCM's for this car can be had used for as little as $18 shipped, which should make troubleshooting a bit easier. Will also be trying to measure resistance on the ac pressure sensors, to eliminate those from the equation. I think if both sensors are good, that can only leave one possible culprit left...and that's the pcm.
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Tom Greenleaf
Ultimate Carjunky
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Jul 15, 2022, 6:09 AM
Post #7 of 35
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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@ back a couple: Flipstyle > understood it's a clunker now that you said and just want to limp it along as much as you can without costing a lot. Got it. IDK, around me cars that old are sometimes plain remarkable so wouldn't want to wreck a good thing. Carry on Hammer is right things are not going to allow compressor till satisfied with list of other things in order and ready. I said (do all the time) charge to spec just BTW within 2 days saw 134a cans for as little as $11 still is going to change fast. Two cans (12oz ea) is so close would be the charge just on the low side a touch. Guessing by pressures not a pest (for me) sun is high, temps swing wildly where I am and spots in area I want to diagnose and do tweak up systems OMG thermometers everywhere. It just gets too hot in areas with a running engine all bets off take it for a ride. That just a comment on boosting. If it's all wrong that will be the problem. Understand the "backyard tech" it's just this is also A/C a study of itself before computer controlled is a pest to learn with live + ongoing changes in temps just while working on it when running. Default is I/we don't suggest guessing by pressures anymore rather start with knowns. No telling what is or was triggered to shut it down sometimes starting over old as this thing is, is the best starting point. Today those two cans over having A/C or not is chump cost for this stuff. Laugh - it was cold here last night odd spring wild weather - never mind cars + house turning on heat and A/C same day someone tell the world it's JULY! Smile, Tom
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flipstyle
User
Jul 18, 2022, 2:34 AM
Post #8 of 35
(4008 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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Will also be trying to measure resistance on the ac pressure sensors, to eliminate those from the equation. I think if both sensors are good, that can only leave one possible culprit left...and that's the pcm. You are nine miles off the mark. It appears you are just going to create more problems then you already have. You are FAR away from blaming a PCM for this issue. Like I said, until the PCM is satisfied with ALL the inputs, it will not turn the AC on. Everything in that diagram plays a part in whether the relay is activated or not. Definitely fair. I had no idea how many inputs and how complex AC systems were before all this. I'm praying this turns out to be a simple fix, but thus far it's not looking too good. So I dug in a bit tonight, but didn't make much progress. First things first, digging around the net I found out that most accords/acuras have a built-in AC/Climate control diagnostic function. I tried various iterations of the HOLD AC/PRESS DEFROSTER 5X, etc...but it didn't do anything. I'm guessing those sequences only apply to newer models, as mine is a 1997 Acura CL 3.0. However, putting the car to the ON position with everything off (AC/fans/defrosters/etc) and pressing and holding both the OFF/Auto buttons simultaneously yielded the following display: https://i.imgur.com/wZj7JCz.jpg Is this valid? I repeated the sequence multiple times and it kept yielding the same result. Mind you, all 4 bars of fan blower indicators on the LCD panel are fine, so that 3rd bar being absent may be a part of the explanation. I always though the code should be a numerical reading, but thought I should throw this out there. Can't find anything on the net about this though. Next I could not seem to find the Low side AC pressure switch in the engine bay. I thought it would have been easy to locate like in the 4 cylinder models, but that's not the case. Should it be located BEFORE the low pressure input port? I found what I believe to be an AC pressure switch located AFTER the low pressure input port on the left side of the engine bay in front of the alternator. I'm 99% sure it's an AC pressure switch because the 2 wires coming into the socket are part of same harness with the AC clutch (single red wire) and the condenser fan. https://i.imgur.com/cQsSLbV.jpg I tested continuity of this switch with the car and AC off and there was continuity (which should mean its working at it should?) The high side refill port is located behind the bumper. I tried to find a high side switch there, but closest I could find was something that may have been it in the following picture: https://i.imgur.com/x5mmwou.jpg Does my vehicle only have 1 ac pressure switch? Rundown of my vehicle: - AC compressor and clutch are good (run fine every time when jumped) - coolant levels good/no air in system - new coolant temp sensor - both radiator and condenser fans are good and run when engine is running. However, I'm a bit concerned that they come on and cycle off a lot. ex: will kick on every 3 minutes, run for 10 seconds, then repeat this cycle So again, curious if that self diagnostic climate control display meant anything.....is the pressure switch that I located high or low side, and is there another pressure switch I'm missing? Thanks again for all the help again!
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 18, 2022, 3:09 AM
Post #9 of 35
(4005 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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Quote Flipstyle "> I had no idea how many inputs and how complex AC systems were before all this.<" Sure is and not necessary IMO. Of all you posted just then, the LED light bar/stack with one out concerns me that whole sealed unit in question. Re the imputs: They make sense and don't at the same time. If no pressure or too low shut down is the default or should be. That and pressure too high, engine temp too high each and many others can shut it down. Some self-reset, some don't. Which one if that's the issue at all is the challenge. Testing these sensors TMK not available (to me anyway) so makes it a parts toss then question the new part now high defective % so if you try "parts tossing" for anything do one thing at a time not confuse whatever with more than one. At some point diagnosis needs all kinds of live info while it's not working makes no sense but a total pro with all the insane costly readers for clues still then make the best educated guess. A/C stinks - it's not DIY friendly and not what you'll find on corrupted YouTube or similar crap isn't verified what you see is true at all! Stinks, ] Tom
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Hammer Time
Ultimate Carjunky
/ Moderator
Jul 18, 2022, 4:16 AM
Post #10 of 35
(4003 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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You know, if you can't identify which components are which, you can't know how they are supposed to work and you can't diagnose anything. Running the Self-diagnosis Function Turn the ignition switch ON (II). After one minute, press both the AUTO and OFF buttons at the same time. While the buttons are pressed, indicator lights A, B, C, D, E and F respectively will come on to indicate a faulty component. NOTE: In case of multiple problems, the respective indicator lights will come on. If indicator lights A, B, C, D and E come on at the same time, there may be an open in the common ground wire of the sensors. Resetting the Self-diagnosis Function Turning the ignition switch OFF will cancel the self-diagnosis function. After service work, run the self-diagnosis function once again to check that there is no other problem. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Jul 26, 2022, 6:57 PM)
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flipstyle
User
Jul 18, 2022, 6:27 AM
Post #11 of 35
(3993 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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OMG Thank you for this! It's not posted anywhere online, so I'm extremely grateful you have an explanation for the codes I was getting. This is all starting to make sense, because I had pulled out my entire dash to replace a leaky heater core about 3 years ago, and since then the AC had never worked, though it worked flawlessly before that. I'm suspecting that I forgot to re-plugin some small items when putting everything back together. So it looks like my evap temperature sensor has an issue, based on my readout. It's actually very possible I didn't even reconnect this sensor at all when I put my dash back in. Especially since I can only get luke warm air even without ac with just the regular fan set to 60 degrees. Curious, do you happen to have a diagram of where the evap sensor is located on my 97 acura cl 3.0? I'm praying it's accessible either behind the glovebox or from the sides of the console under the footwell....or perhaps even behind the stereo cluster in the center of the dash. Any help is greatly appreciated, can't thank you enough!
(This post was edited by Hammer Time on Jul 18, 2022, 6:44 AM)
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Hammer Time
Ultimate Carjunky
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Jul 18, 2022, 6:42 AM
Post #12 of 35
(3990 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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Please stop using the quote feature. It is adding way too much to this thread. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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flipstyle
User
Jul 18, 2022, 4:32 PM
Post #13 of 35
(3965 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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Thank you so much again, Hammer
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flipstyle
User
Jul 18, 2022, 9:21 PM
Post #14 of 35
(3952 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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So I looked around and was able to remove every fault except for the Evaporator Temperature Sensor, as shown in the following image: Turns out my blend door module wasn't fully plugged in. Unfortunately, nothing I could do with the actual evap sensor itself, except checking that it was plugged in properly and the wiring wasn't compromised. I assume actually testing the probe requires removing the entire dashboard to open up the hvac case since a lot of the screws up top aren't very accessible with just the glovebox removed. I'm assuming I have the right part (circled in red): I tried testing for voltage at the male end of the evap temp sensor plug, and could not get any reading no matter what climate control mode was selected. Probably wouldn't get voltage anyways, but tried just in case. 3 things: 1) does the self diagnostic mode showing an error with the Evap Temperature Sensor mean that the evap sensor is the ONLY possible culprit, or is this a general fault code that could also indicate other components in the system? No check engine light. No codes stored. 2) Would purchasing and installing a new sensor clear this error even if the sensor probe itself isn't installed inside the HVAC and just dangling outside (even if erratically?). So I can know if I'm barking up the wrong tree before ripping up the dash again. In other words, is there a way to test if the probe is indeed the culprit WITHOUT ripping out the dash and opening up the hvac unit? 3) Is the evaporator temp sensor a substitute for the low side AC pressure switch on my vehicle? Again, I could only locate one switch which was located next to the condenser fan (after the Low refill port and before the High refill port) Thank you!
(This post was edited by flipstyle on Jul 18, 2022, 9:55 PM)
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flipstyle
User
Jul 19, 2022, 4:11 PM
Post #16 of 35
(3924 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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Thanks so much, Hammer. I'm going to have to find a creative way to test the resistance. Thinking perhaps taking a heatgun to the outside of the HVAC box for awhile will aid in my testing. Curious: is any voltage supposed to flow into or out of the evap temp sensor? As I stated earlier, I tried testing for voltage from the input plug (not the sensor itself) and got nothing, either with the car off or car on utilizing a combination of all the fan/ac modes. Wow, had no idea that switch I was referring to was an ambient temp sensor. Do you happen to have a diagram of all the switches located on my vehicle pertaining to the cooling/AC? I know where the thermostat and coolant switches are, but wondering if I'm missing any other ones. Thanks again!
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Hammer Time
Ultimate Carjunky
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Jul 19, 2022, 4:23 PM
Post #17 of 35
(3918 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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I don't know what you could possibly need a heat gun for. The highest temp to test at is 86 deg. You would have to make it cold to test the other end of the spectrum. This sensor deals in resistance, don't worry about voltage. No, I don't have any more diagrams. It only has one pressure sensor in the right front of the engine compartment. If you are intent on making these diagnosis and repairs yourself, then you should look into a single car subscription to Alldata. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Jul 19, 2022, 4:24 PM)
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flipstyle
User
Jul 19, 2022, 6:27 PM
Post #18 of 35
(3909 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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Perfect. Yes, I think I do need a subscription. Will look into that. Again, thanks for the guidance and aid.
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flipstyle
User
Jul 25, 2022, 8:17 PM
Post #19 of 35
(3872 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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Unfortunately, have an unfruitful update. I received my replacement (brand new OEM) evaporator temp sensor today. Installed it with the sensor hanging out in the open (ambient temp was around 90 today). And unfortunately it didn't change a thing. AC compressor and fan do not engage. Same readout fault on the climate control display, though I'm skeptical that it's accurate in the first place. I went so far as to test the resistance on both the new evap temp sensor and the old one. And both were well within range for the outside temp. Now I'm stumped. Here's everything that I know: 1) low side freon pressure is good (with ac compressor and condenser fan jumped). Around 30psi. 90psi when the system is off. I've yet to get a reading on the high side port. Perhaps next? 2) I'm pretty sure the physical AC button/switch at the console is good. Because when I turn the AC on, the actuator behind the glovebox (located to the right of the condenser unit) activates and opens up a blower door, then closes it when I turn the AC off. So it's getting/triggering a signal. 3) Again, both the ac compressor and condenser fan turn on (and stay on) when both relays are jumped under the fuse box (near the firewall) on the copper pins. Also, the condenser fan spins when the radiator fan comes on (to cool the motor after running awhile). So I'm sure both are still good. 4) Both blend door actuators to on the passenger side appear to be functioning as they should, and moving/activating with the proper commands Just for fun, I tested the voltage on the relay sockets for both the ac compressor and condenser fans. The copper pins (3 & 5) are ALWAYS hot and read ~13 volts. Doesn't matter if the car is off/on, or the ac is off or on. The leads are hot 24/7. Should they be this way? Is there any other testing I could do on the sockets themselves to see whether or not the proper signals are reaching them? Got to my pcm today. Tried to locate the A27, A17, C5, D11 wires from the diagram supplied. But unsure how to test them, or in what combinations. I think I'll have to find an actual pin out diagram of the ecm for this. I assumed the blue plug pictured (other 2 plugs are gray) were for the cooling system, so I tested the appropriate wires (green wires being ground and red wires being positive) and got full time hot reads (12 volts) when the car was ON (doesn't matter whether ac was on or off). And 0 volts while the car was off. Not even sure if I was doing this correctly or testing the right wires. Sorry for the novel, but that's where I'm at. Please let me know if I'm in over my head, but I feel as though I'm checking off possible culprits slowly but surely. I'd just like to exhaust all possiblities within my capacity before biting the bullet and hitting a shop. Thanks again
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flipstyle
User
Jul 25, 2022, 8:50 PM
Post #20 of 35
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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Also, it just dawned on me. Are both the condenser fan and radiator fan supposed to come on when the ac compressor is activated? Because when I jump the ac compressor and condenser fan manually, the radiator fan does not turn on. However, BOTH fans turn on when the engine gets warm and is colling itself off. Odd.
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flipstyle
User
Jul 26, 2022, 4:58 AM
Post #22 of 35
(3857 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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Fair enough. I appreciate the honesty. Unfortunately, I'm not willing to shell out the $1k for a diagnostic tool that's able to work with A/C systems, especially not for a car of this value. So I'll keep fiddling with things (AC is already broken, not a huge concern) until I give up and hopefully summer is over.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 26, 2022, 6:25 AM
Post #23 of 35
(3851 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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Quick read > flipstyle, if you keep jumping things THAT IS THE PROBLEM! Blow things that matter up to wrecking whole system. Voltages are NOT all bat+ voltage so keep on doing that + find out how much damage you caused never mind the original issue, Tom
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jul 26, 2022, 6:52 AM
Post #25 of 35
(3842 views)
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Re: AC Compressor and condenser fan ONLY come on when relays are jumped
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New England! Places to be a shop are now almost only Dunkin' Donuts. Just imagine selling drive-thru coffee (mostly) @$5 a cup is more cost efficient that one aspect of working on vehicles never mind A/C. Guilty as charged will refer most here to pros in biz for it (one locally!!!!) others quit too costly to do it for $1,000/ hr. (if doable) one shop bay now 2M so do the math. I go with the car giving me rare but happens - fits - none for some years. Toto, we're not in Kansas anymore ?? Tom
(This post was edited by Tom Greenleaf on Jul 26, 2022, 6:58 AM)
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