99wdptl

**I did a search and found nothing in regards to this issue**

Ok, so a few weeks ago while driving to work my A/C compressor locks up on me not an issue i get the thing replaced and all that good stuff.

So about 2 days after the repair i notice (it was hard not to) that the serpentine belt is screaming at me whenever i start the car. So i take it back to the shop, they said they couldn't reproduce the symptoms i was reporting so i told them to keep it over night i knew it would do it in the a.m

Well it did and they have been trying to figure the issue out for about a week now. So i call them today to check the status and apparently the A/C compressor is stuck on. They think this is happening b/c the ECU has gone bad... That is a new one for me i didn't think the ECU had anything to do with the A/C system...

So here is my question, does the ECU actually control the A/C system in anyway, and does anyone have any clue as to what else could be causing this issue? Any help would be greatly appreciated.

acutee

They are doing a guessing work, or try to charge for something else, then replacing the ac unit again; to me, they are trying to avoid free warranty work. It is the compressor problem. Have them replace the compressor again under warranty.

99wdptl

This is a very good point. See they told me "this is why the old one went out" and i don't get that b/c the belt has never made that noise before.... Well he said call him back tomorrow he was going to test some other relays to narrow down the issue, this guy has been honest and fair with me in the past so i would hate to assume that this is what he is doing but you never know.....

**On a side note the PCM does control/relays the signal that goes to the compressor All Data FTW **

acutee

You are correct, the pcm does controll the compressor for climate control; but if that was the case, then your origninal compressor wasn't bad. It was the pcm issue in the first place. Unless, your compressor and pcm are both went bad at the same time or failing one after another. The hard part is to pinpoint the root problem, otherwise they will keep replacing good parts for troubleshooting and narrowing down the problem.

99wdptl

Well the old compressor locked up driving to work and caused the old Surp belt to fly/break off that's how i know it went bad (144K on the car i think it was time). They are saying that the belt is making noise b/c the compressor is always on due to the fact the PCM wont stop sending signal to the relay. Well if that is the case why did the belt not make any noise from the get go (with the old compressor), and why is this any different then when you start the car with the A/C on? Its not, the only reason the belt would be yelling at me is if the compressor was locking up on start up........

Ok i see your point, sounds to me like your right . Did not want that to be the outcome.........

jdjohn84

Seems like it would be a bad climate control unit (thing in the dash with AUTO button) instead of the ECU. Maybe the climate control unit is sending a constant ON signal to the compressor.

They should be able to pull the a/c fuse or relay to prevent the compressor from coming on, and then see if the belt stops squeaking. If it still squeaks, the tensioner is probably bad.

The ECU does tell the engine to rev up a little when it expects the compressor to come on, and maybe tell the compressor to turn OFF if there is insufficient pressure in the a/c system, but I can't think of why the ECU would give a constant ON signal.

eg5

iTrader: (4)

you need to take this to another shop or the dealership asap.
yes pcm controls ac engagement and like stated above compensates engine operations to keep it from stalling at idle etc etc.

this is my theory, the shop that installed your ac compressor either did not use correct space shims between the clutch and pulley(thus compressor always engaged) this is if they used factory acura parts(compressor assembly, coil, clutch and pulley are sold seperately)
yes it is possible to have a bad ac control panel or bad pcm. but absolutely not in this case here. i am certain the noise heard by you is due to
a worn ac tensioner, a worn tensioner sill rattle chatter worn pulley squeek type sound. all depends on how worn the tensioner is
bad belt
residue from dirty job that spilled on to nearby pulleys.
...im sorry if i come across like a douche but this here seems like a shady shop or just inexperienced techs.
...ask them how did you determined the pcm was bad?
...ask them to show you the voltage reading at the ac compressor terminal when problem occurs(yeah this is a stretch here)
hope this helps

jdjohn84

Did they replace the whole compressor last time, or just the clutch? If just the clutch, then improper shimming could definitely be the problem. I would think a new or reman compressor would come pre-shimmed properly, but only replacing a clutch would require more attention to the shims, AND proper grounding of the clutch or it might stay engaged.

99wdptl

Thank you for the information, you see when it first happened i thought it could be a bad tensioner pulley due to the age of the vehicle, and its only on cold starts after the car has sat for a while, even if the PCM was bad and was leaving the the A/C compressor engaged all the time that would not cause this noise, i mean whats the difference between starting the car with a compressor "stuck" on or turned on? I don't think there is..... Its just on as far as the car is concerned....


They replaced the WHOLE Compressor, and the evaporator, and something else last time. They also vacuumed the system and recharged it.

eg5

iTrader: (4)

any updates?

99wdptl

sorry for the late response, finals this week so i am a little busy....


I went and talked to the guy, we pulled out the center console to get to the PCM and the Climate control, tested the signal and it seemed to be normal not indicating that the PCM was the issue. It looks like when BB(Best Buy) installed my head unit they spliced some wires and tapped into the power wires for the Climate control and we think that might be sending a full power signal to the compressor and causing the problem.

The compressor is not bad, the reason the belt is screaming at me is b/c the way the compressor is running now it's not allowing the compressor to cycle, so that is causing too much pressure to build up in the lines and the lines are freezing up causing the compressor to jam

But its still there i hate electronic issues, they take forever to fix and are expensive as hell.....

99wdptl

ok, just got off the phone with the guy. When Best buy tapped my climate control power wire to install my EQ they shorted the system out and caused the unit to stay on all the time ( I am guessing the wire they tapped into was the wire that initiates the compressor cycle sequence w/e) This fired the Climate control unit (Not the PCM ) and that part is on order. Price shouldn't be all that bad (they sell on ebay for $50) compared to what the PCM would have cost $1000~ so i should have my baby back on Wednesday at the latest

This just goes to show NEVER let those jacka$$'s at Best Buy touch your crap, I was lazy took it to them and look where it got me

P.S The Best Buy comment is some what of an over generalization, I am sure some people there know what they are doing i just had some really bad luck. The actions of one can't lay shame on a whole.....

eg5

iTrader: (4)

to my understanding, the built up pressure wont cause belts to squeek. excessive pressure in the ac system will cause one the ac pressure switch to send a signal to stop the cycling of the compressor. but since youve determined the problem being that of a short, the compressor will continue to run until the check valve on the compressor gives and out comes the freon. this will cause a loud psssshshhhhhhhhh

UNCatTech

Never take anything to BB to be fixed. I have a computer that my dad took to them, they told him it couldn't be fixed. I reinstalled the OS and it works fine. I know a couple of other people that have taken computers to them and they screw them up.

99wdptl

ok, so i finally get my car back today. The problems were this;

Best Buy taped into my climate control unit to run my EQ and that shorted out the climate control unit. It would send signal to the PCM that the defrost was always on, thus leaving the compressor on all the time. *Solution Replace Climate Control Unit* $197.00 parts only no labor charge.

The belt chatter was never really sorted out, so they just replaced the belt, belt tensioner, and compressor for good measure. All was under warranty no charge

So after 3 weeks and a lot of frustration i get my car back and i feel they did a good job, electrical issues are always a PIA to track down and fix, but all is now working as it should.