Author Topic: Air con starts working suddenly after 15 minutes  (Read 833 times)

pintofale

  • New Member
  • Posts: 9
  • Country: gb
  • My Honda: Jazz
Air con starts working suddenly after 15 minutes
« on: May 13, 2019, 04:30:16 PM »
Hi all,

Tried the air con on my 2010 1.3 EX today for the first time (bought it last autumn).  I didn't think it was working at first because I had warm air coming in, then after 15 minutes it very suddenly went very cold!  On the return leg I had the same issue - it was warm at first then all of a sudden kicked it.  Stopped off on the way (for a sandwich if you must know) and the same thing happened for the third time.  I can't believe it's a loose wire (too much of a coincidence) or something wrong with the system (once it worked, it worked reeeeally well and kept working), I can only think it's something to do with it taking a while to cut in, maybe due to being too hot?  Anyone have any insight?  It's going to be a bit annoying because my normal run to work is 14 minutes!

Cheers,
Neil.

culzean

  • Approved Member
  • *
  • Posts: 5253
  • Country: england
Re: Air con starts working suddenly after 15 minutes
« Reply #1 on: May 13, 2019, 04:47:30 PM »
Could be a problem with gas, pressure sensors or clutch solenoid gap there is also a high temperature sensor on compressor and a cold sensor on the cold heat exchanger . The solenoid energises and pulls a clutch plate to drive compressor, the gap has to be tight ( 0.35 to 0.6mm IIRC ).  The solenoid is controlled by a relay in the fusebox, and have been known to play up intermittently or stick closed and drain your battery.

If the aircon blows cold when it does work it is unlikely to be low gas.
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

sparky Paul

  • Approved Member
  • *
  • Posts: 1288
  • Country: gb
  • My Honda: 2015 GG6 Jazz EX 1.4 I-VTEC / 2008 GE3 Jazz SE 1.4 i-DSI
Re: Air con starts working suddenly after 15 minutes
« Reply #2 on: May 13, 2019, 06:44:17 PM »
Low gas, it just needs regassing. As the engine bay warms up, the gas remaining in the system warms up, expands, and is enough to trigger the low pressure switch and allow the system to run.

The good news is that there must be a significant amount of gas left, and that means that there are probably no leaks.

The refrigerant gas leaks past the seals as they dry out when the system goes unused through the winter. Make sure you use the aircon at least once a week throughout the winter to distribute oil through the system, wetting the seals and minimising refrigerant loss.

Jocko

  • Approved Member
  • *
  • Posts: 4493
  • Country: scotland
  • Fuel economy:
  • My Honda: 2006 GD5 Jazz 1.2 i-DSi S in Vivid Blue Pearl
Re: Air con starts working suddenly after 15 minutes
« Reply #3 on: May 13, 2019, 08:58:26 PM »
If the air con has not been run since buying the car last autumn I am not surprised the gas is low. Rotary seals need to be run to keep lubricated and sealing. I had air con on my Volvo S40 and it was never off. In the winter it keeps the air inside the car dry (and the carpets), leading to no condensation on the windows, and in the summer it keeps the car cool. You couldn't run the demist without the air con coming on automatically. The car also had a sunroof, but it was never open.

pintofale

  • Topic Starter
  • New Member
  • Posts: 9
  • Country: gb
  • My Honda: Jazz
Re: Air con starts working suddenly after 15 minutes
« Reply #4 on: May 16, 2019, 03:33:36 PM »
Ok, thanks all, I will look at getting it re-gassed.

pintofale

  • Topic Starter
  • New Member
  • Posts: 9
  • Country: gb
  • My Honda: Jazz
Re: Air con starts working suddenly after 15 minutes
« Reply #5 on: July 12, 2019, 04:43:27 PM »
I got it regassed a while ago but it didn't make any difference.  And as of the last couple of weeks it just doesn't work at all.  Seems like it must be an electrical problem.  Does anyone have any clever guesses as to the most likely cause? 

culzean

  • Approved Member
  • *
  • Posts: 5253
  • Country: england
Re: Air con starts working suddenly after 15 minutes
« Reply #6 on: July 13, 2019, 09:38:54 AM »
Do the engine and condenser fans come on when you turn aircon on ?  and does the clutch pull in ( you can open the bonnet and stand at drivers side and look at the pulleys below the alternator ( may need a torch ) at the very lowest pulley you can see , that is the compressor drive pulley and it has a 'clutch plate' connected to the compressor drive shaft and a magnetic solenoid that energises to pull the clutch plate onto the rotating pulley.  if the aircon is turned off you will see that centre of the pulley ( clutch plate ) is not rotating with the pulley, when aircon is turned on the clutch plate will be pulled in ( that is when fans run as well ) and released  ( when fans stop ) on and off about every 10 seconds to drive gas around the aircon system.  Have to say that low gas is normally the reason for aircon compressor not being engaged as it is a safety device to stop compressor damage.  I did have the actual clutch coil fail on my Civic which I replaced myself ( a real PITA ).  There are other threads on here about aircon so do a search.......
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

sparky Paul

  • Approved Member
  • *
  • Posts: 1288
  • Country: gb
  • My Honda: 2015 GG6 Jazz EX 1.4 I-VTEC / 2008 GE3 Jazz SE 1.4 i-DSI
Re: Air con starts working suddenly after 15 minutes
« Reply #7 on: July 13, 2019, 09:59:38 AM »
Have to say that low gas is normally the reason for aircon compressor not being engaged as it is a safety device to stop compressor damage.

...or over- gassing, the pressure switch is two way and protects the pump from  over filling. Did you get a report indicating the quantity of gas and oil put back into the system? It should match the quantity on the sticker under the bonnet, and I know they do get it wrong on occasions... particularly with some of these fully automated recharging stations.

Culzean's post is spot on, check to see if the clutch is operating first. If not, then gas pressure is too low/high, or there is a fault with clutch, associated wiring or a system sensor - a diagnostic might be the way to go. It will tell you if anything is preventing the system from running, or if the system should be running.

The initial symptoms of not running when the engine was cold did point to borderline low gas, and you seem to have gone from working sometimes, to not working at all after regassing?

pintofale

  • Topic Starter
  • New Member
  • Posts: 9
  • Country: gb
  • My Honda: Jazz
Re: Air con starts working suddenly after 15 minutes
« Reply #8 on: July 15, 2019, 08:39:39 PM »
Thanks for the replies.  I can see the compressor pulley below the alternator and water pump.  When I turn on the air con the radiator cooling fans come on, but I do not see anything different on that bottom pulley.  I am not sure what I'm looking for but there is some sort of plate on the end face of that pulley which does not move.  It sounds like it should be doing something more interesting.  So I guess I have either a bad pressure sensor or a bad compressor.

pintofale

  • Topic Starter
  • New Member
  • Posts: 9
  • Country: gb
  • My Honda: Jazz
Re: Air con starts working suddenly after 15 minutes
« Reply #9 on: July 15, 2019, 08:48:13 PM »
For starters I will try shorting the pins on the pressure sensor connector, if that works I will try a new sensor.  If not I think I will have to get the bottom engine cover off and stick 12v into the compressor clutch solenoid.

culzean

  • Approved Member
  • *
  • Posts: 5253
  • Country: england
Re: Air con starts working suddenly after 15 minutes
« Reply #10 on: July 16, 2019, 04:26:53 PM »
Thanks for the replies.  I can see the compressor pulley below the alternator and water pump.  When I turn on the air con the radiator cooling fans come on, but I do not see anything different on that bottom pulley.  I am not sure what I'm looking for but there is some sort of plate on the end face of that pulley which does not move.  It sounds like it should be doing something more interesting.  So I guess I have either a bad pressure sensor or a bad compressor.

The plate you can see is the part of the clutch that is connected to compressor shaft, if it is not spinning with the pulley it means that for whatever reason there is no power on the clutch solenoid, or their may be power there but solenoid coil that magnetises the clutch in open circuit.   You have already found the clutch relay in the fusebox,  you can either short across the two large pins of the relay ( the main current carrying poles ) with a paper clip or if you have a meter put a voltmeter on DC and low volt range and see if there is power going to coil of relay ( two small pins of relay - it is a pity that most relays do not have an LED indicator wired across coil so that it lights up when power is present on relay coil, they are available but cost maybe 50 pence more, a no-no for cost concious car companies ) if yu can see 12 volts across the coil of relay it means system is trying to energise the relay.   


An easy check on continuity of circuit through clutch coil is if you short the two large relay pins / sockets out you have eliminated all the sensors and ECU out and are applying power directly to the clutch coil ( the only thing in circuit beside the coil is the over-temperature thermostat contact on the compressor ). You can measure between the two large pin sockets that the relay plugs into in fusebox and should get a reading of 12 volts, one of the large sockets goes straight to battery via a fuse and the other socket goes to earth via the clutch coil and over-temp cut out contact,  if you do not see 12 volts across the sockets it means that the circuit through coil and cut-out is broken, the other way is to check sockets to earth with a voltmeter and find which socket is 'live' and then switch to resistance and check the other socket to an earth on the car body, you should read about 4 ohms through the coil.
« Last Edit: July 16, 2019, 04:30:52 PM by culzean »
Some people will only consider you an expert if they agree with your point of view or advice,  when you give them advice they don't like they consider you an idiot

pintofale

  • Topic Starter
  • New Member
  • Posts: 9
  • Country: gb
  • My Honda: Jazz
Re: Air con starts working suddenly after 15 minutes
« Reply #11 on: July 16, 2019, 08:15:23 PM »
Thanks for the detailed reply.  I tried shorting the pressure sensor connector pins, I could turn the cooling fans on and off and change the engine revs by opening and closing the contacts, but the clutch plate did not move.  So I suspect the solenoid or relay.  I am not sure which relay to check but I will try to work it out and try that next.

pintofale

  • Topic Starter
  • New Member
  • Posts: 9
  • Country: gb
  • My Honda: Jazz
Re: Air con starts working suddenly after 15 minutes
« Reply #12 on: July 17, 2019, 08:27:54 PM »
Aha, faulty relay.  Clicks but contacts don't close.  New one on order.  Many thanks for all of the useful information.

pintofale

  • Topic Starter
  • New Member
  • Posts: 9
  • Country: gb
  • My Honda: Jazz
Re: Air con starts working suddenly after 15 minutes
« Reply #13 on: August 13, 2019, 08:18:19 AM »
Just to close the thread, changing the relay for a 3 Osram one from ebay did the job and it's been working well for the last few weeks.  I now carry a spare relay as well as spare fuses.

Tags:
 

Back to top