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A/c completely dead, need advice



 
 
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  #1  
Old August 11th 06, 03:32 PM posted to rec.autos.tech
Masospaghetti
external usenet poster
 
Posts: 48
Default A/c completely dead, need advice

Hey all,

Car is a 1986 Honda CRX. Where should I start looking for trouble if
pushing the A/C button does _nothing_? No increased idle, no condenser
fan, and obviously no cooling. the only thing that happens is the little
"A/C" light turns on.

Thanks
James
Ads
  #2  
Old August 11th 06, 05:18 PM posted to rec.autos.tech
Pete C.
external usenet poster
 
Posts: 458
Default A/c completely dead, need advice

Masospaghetti wrote:
>
> Hey all,
>
> Car is a 1986 Honda CRX. Where should I start looking for trouble if
> pushing the A/C button does _nothing_? No increased idle, no condenser
> fan, and obviously no cooling. the only thing that happens is the little
> "A/C" light turns on.
>
> Thanks
> James


Take it to a reputable shop, or buy a service manual. Might want to
spend the $15 on a service manual first anyway so you can check the
simpler stuff yourself. Either way, if the system needs evac and
recharge you're going to need to bring it to a shop for that due to
freon regulations.

I recently repaired the A/C on my truck. I took it to a shop for
diagnosis which revealed leaking compressor seals. I couldn't justify
the cost to replace with new for a 9yr old truck so I had them leave the
system empty. I then replaced the compressor, orifice tube and
accumulator dryer myself using inexpensive rebuilt parts. Once I was
done I brought the truck back to the shop for evac and recharge.

The A/C is now working fine and I saved quite a bit of money. Of course
you can't expect the shop to warranty anything other than their
refrigerant charge, but considering the money saved I could do all the
same again and still be ahead.

Pete C.
  #3  
Old August 11th 06, 07:38 PM posted to rec.autos.tech
[email protected]
external usenet poster
 
Posts: 17
Default A/c completely dead, need advice


Pete C. wrote:
> Masospaghetti wrote:
> >
> > Hey all,
> >
> > Car is a 1986 Honda CRX. Where should I start looking for trouble if
> > pushing the A/C button does _nothing_? No increased idle, no condenser
> > fan, and obviously no cooling. the only thing that happens is the little
> > "A/C" light turns on.
> >
> > Thanks
> > James

Most likely due to an empty system. The low pressure switch is
preventing the clutch from engaging.

To diagnose, find the LPS on the accumulator and jumper the connection
while the a/c is on. If the clutch kicks in, that is the problem.
Don't run it for long. Just verify the clutch kicks in. If the clutch
does not engage, you have other problems. Get a manual and a DVM and
start tracing.

With an old R-12 system, it will probably not be cost effective to get
it fixed and charged with R-12.

What I would recommend, providing you have the tools, is to convert to
R-134.

First you need to figure out where the R-12 leaked out. Most likely on
the high pressure(hot side) of the compressor. Probably the crimp
right next to the compressor.

Replace whatever is leaking. Replace all of the o-rings in the system.
Replace the orifice tube. Replace the accumulator.

Drain all of the oil you can out of the hoses/system.

You can get little adapter ports to change the R-12 ports to R-134.
Get those and screw onto your existing ports.

Fill the system with the recommended amount of PAG oil(it will say on
the compressor).

Seal the sytem up. Evacuate the system(requires a vacuum pump).

Charge with 80% of the recommended charge for R-12 with R-134a.

Enjoy the cold.

  #4  
Old August 11th 06, 11:54 PM posted to rec.autos.tech
John S.
external usenet poster
 
Posts: 981
Default A/c completely dead, need advice


Masospaghetti wrote:
> Hey all,
>
> Car is a 1986 Honda CRX. Where should I start looking for trouble if
> pushing the A/C button does _nothing_? No increased idle, no condenser
> fan, and obviously no cooling. the only thing that happens is the little
> "A/C" light turns on.
>
> Thanks
> James


Suggest that you take the car to a dealer and have them fix the car.

  #5  
Old August 12th 06, 04:25 AM posted to rec.autos.tech
Masospaghetti
external usenet poster
 
Posts: 48
Default A/c completely dead, need advice

wrote:
> Pete C. wrote:
>> Masospaghetti wrote:
>>> Hey all,
>>>
>>> Car is a 1986 Honda CRX. Where should I start looking for trouble if
>>> pushing the A/C button does _nothing_? No increased idle, no condenser
>>> fan, and obviously no cooling. the only thing that happens is the little
>>> "A/C" light turns on.
>>>
>>> Thanks
>>> James

> Most likely due to an empty system. The low pressure switch is
> preventing the clutch from engaging.


The system has plenty of refrigerant. I would have expected that the at
least the condenser fan and boosted idle to kick in if it was just low
on refrigerant.

I tried jumping the clutch relay and the compressor engages. the system
actually cools extremely well.

I figured it would be low refrigerant when I first saw the car too, but
I pushed on the low-side schrader and got a huge blast coming out.

>
> To diagnose, find the LPS on the accumulator and jumper the connection
> while the a/c is on. If the clutch kicks in, that is the problem.
> Don't run it for long. Just verify the clutch kicks in. If the clutch
> does not engage, you have other problems. Get a manual and a DVM and
> start tracing.
>
> With an old R-12 system, it will probably not be cost effective to get
> it fixed and charged with R-12.
>
> What I would recommend, providing you have the tools, is to convert to
> R-134.
>
> First you need to figure out where the R-12 leaked out. Most likely on
> the high pressure(hot side) of the compressor. Probably the crimp
> right next to the compressor.
>
> Replace whatever is leaking. Replace all of the o-rings in the system.
> Replace the orifice tube. Replace the accumulator.
>
> Drain all of the oil you can out of the hoses/system.
>
> You can get little adapter ports to change the R-12 ports to R-134.
> Get those and screw onto your existing ports.
>
> Fill the system with the recommended amount of PAG oil(it will say on
> the compressor).
>
> Seal the sytem up. Evacuate the system(requires a vacuum pump).
>
> Charge with 80% of the recommended charge for R-12 with R-134a.
>
> Enjoy the cold.
>


thanks for the advice.
  #6  
Old August 12th 06, 04:59 AM posted to rec.autos.tech
Pete C.
external usenet poster
 
Posts: 458
Default A/c completely dead, need advice

Masospaghetti wrote:
>
> wrote:
> > Pete C. wrote:
> >> Masospaghetti wrote:
> >>> Hey all,
> >>>
> >>> Car is a 1986 Honda CRX. Where should I start looking for trouble if
> >>> pushing the A/C button does _nothing_? No increased idle, no condenser
> >>> fan, and obviously no cooling. the only thing that happens is the little
> >>> "A/C" light turns on.
> >>>
> >>> Thanks
> >>> James

> > Most likely due to an empty system. The low pressure switch is
> > preventing the clutch from engaging.

>
> The system has plenty of refrigerant. I would have expected that the at
> least the condenser fan and boosted idle to kick in if it was just low
> on refrigerant.
>
> I tried jumping the clutch relay and the compressor engages. the system
> actually cools extremely well.
>
> I figured it would be low refrigerant when I first saw the car too, but
> I pushed on the low-side schrader and got a huge blast coming out.
>
>
> thanks for the advice.


Would have been helpful to include that information in the original
post, we aren't mind readers. At any rate if you've traced the problem
that far it would seem the problem is the clutch relay, one of the
pressure switches the wiring from the pressure switches or the switch on
the dash. A factory wiring diagram would be a big help in isolating it.

Depending on the vehicle you may be able to replace some of the pressure
switches without having to evacuate and recharge the system, but you'll
need the manual to tell you that. If not you'll need to take it
somewhere to have them recover the refrigerant so you can change the
switch and then have them put the refrigerant back if you find the
switch is at fault.

Pete C.
  #7  
Old August 12th 06, 03:13 PM posted to rec.autos.tech
Masospaghetti
external usenet poster
 
Posts: 48
Default A/c completely dead, need advice

I just wanted to know what could cause the system to be _completely_
dead, because usually the fans at least turn on. I tried posting about a
week ago with a hugely long description and didn't get a single response.

i've gone through and tested the following components, which tested OK:

low pressure switch
a/c thermostat
a/c delay timer
a/c relay
clutch relay
a/c clutch
a/c diode
radiator fan relay
a/c switch

none of the relays are even getting a signal. is there some control box
that the button goes to that might be bad?

Thanks
-James

John S. wrote:
> Is there some reason you didn't include this in the first message? The
> first message reads like someone who knows nothing about cars.
>
>
> Masospaghetti wrote:
>> wrote:
>>> Pete C. wrote:
>>>> Masospaghetti wrote:
>>>>> Hey all,
>>>>>
>>>>> Car is a 1986 Honda CRX. Where should I start looking for trouble if
>>>>> pushing the A/C button does _nothing_? No increased idle, no condenser
>>>>> fan, and obviously no cooling. the only thing that happens is the little
>>>>> "A/C" light turns on.
>>>>>
>>>>> Thanks
>>>>> James
>>> Most likely due to an empty system. The low pressure switch is
>>> preventing the clutch from engaging.

>> The system has plenty of refrigerant. I would have expected that the at
>> least the condenser fan and boosted idle to kick in if it was just low
>> on refrigerant.
>>
>> I tried jumping the clutch relay and the compressor engages. the system
>> actually cools extremely well.
>>
>> I figured it would be low refrigerant when I first saw the car too, but
>> I pushed on the low-side schrader and got a huge blast coming out.
>>
>>> To diagnose, find the LPS on the accumulator and jumper the connection
>>> while the a/c is on. If the clutch kicks in, that is the problem.
>>> Don't run it for long. Just verify the clutch kicks in. If the clutch
>>> does not engage, you have other problems. Get a manual and a DVM and
>>> start tracing.
>>>
>>> With an old R-12 system, it will probably not be cost effective to get
>>> it fixed and charged with R-12.
>>>
>>> What I would recommend, providing you have the tools, is to convert to
>>> R-134.
>>>
>>> First you need to figure out where the R-12 leaked out. Most likely on
>>> the high pressure(hot side) of the compressor. Probably the crimp
>>> right next to the compressor.
>>>
>>> Replace whatever is leaking. Replace all of the o-rings in the system.
>>> Replace the orifice tube. Replace the accumulator.
>>>
>>> Drain all of the oil you can out of the hoses/system.
>>>
>>> You can get little adapter ports to change the R-12 ports to R-134.
>>> Get those and screw onto your existing ports.
>>>
>>> Fill the system with the recommended amount of PAG oil(it will say on
>>> the compressor).
>>>
>>> Seal the sytem up. Evacuate the system(requires a vacuum pump).
>>>
>>> Charge with 80% of the recommended charge for R-12 with R-134a.
>>>
>>> Enjoy the cold.
>>>

>> thanks for the advice.

>

  #8  
Old August 12th 06, 04:31 PM posted to rec.autos.tech
Pete C.
external usenet poster
 
Posts: 458
Default A/c completely dead, need advice

Masospaghetti wrote:
>
> I just wanted to know what could cause the system to be _completely_
> dead, because usually the fans at least turn on. I tried posting about a
> week ago with a hugely long description and didn't get a single response.
>
> i've gone through and tested the following components, which tested OK:
>
> low pressure switch
> a/c thermostat
> a/c delay timer
> a/c relay
> clutch relay
> a/c clutch
> a/c diode
> radiator fan relay
> a/c switch
>
> none of the relays are even getting a signal. is there some control box
> that the button goes to that might be bad?
>
> Thanks
> -James


In at least some vehicles the A/C command from the dash switch routes
through the ECM and then to the A/C compressor clutch relay. This allows
the ECM to disengage the A/C clutch momentarily during hard acceleration
/ high engine load to recover the HP used by the A/C compressor and give
better performance.

You could have a failed connection in wiring to / from the ECM, or you
could potentially have a blown output on the ECM which could be and ECM
failure itself, or be caused by a short circuit further downstream that
could kill another ECM output if the ECM is replaced without resolving
the real problem.

Again a factory wiring diagram or at least a look at one to collect the
relevant information would be a big help here.

Pete C.
  #9  
Old August 14th 06, 08:48 AM posted to rec.autos.tech
Ted Mittelstaedt
external usenet poster
 
Posts: 696
Default A/c completely dead, need advice


"Pete C." > wrote in message
...
> Masospaghetti wrote:
> >
> > Hey all,
> >
> > Car is a 1986 Honda CRX. Where should I start looking for trouble if
> > pushing the A/C button does _nothing_? No increased idle, no condenser
> > fan, and obviously no cooling. the only thing that happens is the little
> > "A/C" light turns on.
> >
> > Thanks
> > James

>
> Take it to a reputable shop, or buy a service manual. Might want to
> spend the $15 on a service manual first anyway so you can check the
> simpler stuff yourself. Either way, if the system needs evac and
> recharge you're going to need to bring it to a shop for that due to
> freon regulations.
>
> I recently repaired the A/C on my truck. I took it to a shop for
> diagnosis which revealed leaking compressor seals. I couldn't justify
> the cost to replace with new for a 9yr old truck so I had them leave the
> system empty. I then replaced the compressor, orifice tube and
> accumulator dryer myself using inexpensive rebuilt parts. Once I was
> done I brought the truck back to the shop for evac and recharge.
>


I've done this myself before, however I have a leak detector, vacuum
pump and guage set, flush gun and can do everything without paying a
shop. Keep in mind that if you get 2 years out of an inexpensive rebuilt
compressor, your doing pretty good.

Ted


  #10  
Old August 14th 06, 12:51 PM posted to rec.autos.tech
Pete C.
external usenet poster
 
Posts: 458
Default A/c completely dead, need advice

Ted Mittelstaedt wrote:
>
> "Pete C." > wrote in message
> ...
> > Masospaghetti wrote:
> > >
> > > Hey all,
> > >
> > > Car is a 1986 Honda CRX. Where should I start looking for trouble if
> > > pushing the A/C button does _nothing_? No increased idle, no condenser
> > > fan, and obviously no cooling. the only thing that happens is the little
> > > "A/C" light turns on.
> > >
> > > Thanks
> > > James

> >
> > Take it to a reputable shop, or buy a service manual. Might want to
> > spend the $15 on a service manual first anyway so you can check the
> > simpler stuff yourself. Either way, if the system needs evac and
> > recharge you're going to need to bring it to a shop for that due to
> > freon regulations.
> >
> > I recently repaired the A/C on my truck. I took it to a shop for
> > diagnosis which revealed leaking compressor seals. I couldn't justify
> > the cost to replace with new for a 9yr old truck so I had them leave the
> > system empty. I then replaced the compressor, orifice tube and
> > accumulator dryer myself using inexpensive rebuilt parts. Once I was
> > done I brought the truck back to the shop for evac and recharge.
> >

>
> I've done this myself before, however I have a leak detector, vacuum
> pump and guage set, flush gun and can do everything without paying a
> shop. Keep in mind that if you get 2 years out of an inexpensive rebuilt
> compressor, your doing pretty good.
>
> Ted


Do you also have a refrigerant recovery / recycling unit and EPA cert.
for refrigerant? I can't justify the time / money / effort for those
given the couple times a decade I might use them. Easier to have the
shop recover, I do the work on the empty system and then have them evac
and recharge.

Pete C.
 




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