Air con out of juice?

tbro · Postby **tbro** » Sat Nov 22, 2008 8:03 pm

Marcusus, got it right this time :lol:

The plug you removed off the receiver dryer will need to be bridged, wire or split pin connecting the terminals (usually two) so basically you are bypassing the L/P switch. You don't need to start the motor, just have ignition on and when you bridge terminals the clutch on the A/C compressor will kick in, you will hear it.
If this happens then you may have low gas pressure (most likely) or faulty switch (not common).
Your next test (with the bridge wire still in place) before you can be sure you have found the fault will be to remove the wire to the compressor (plug) and check if power to plug. If so your clutch is stuffed, common if A/C is used all the time.

The best advise I can give you and anyone doing electrical fault finding, especially if doing vehicle electronics is start at the power source and systematically follow wiring diagrams and DON'T skip any sections, because this will be where the problem will be. When I was doing training with apprentices and tradies I would give them a yellow highlighter, so they could mark out the wiring diagrams making it easier to follow them especially when you have 32 wires in 1 plug.

Hopes this helps.
Good luck and remember its usually the little thing that bring us undone :lol:

Terry

MX5CHIC · Postby **MX5CHIC** » Sat Nov 22, 2008 8:30 pm

It sounds that you have basic knowledge on the use of a Multimeter - after removing the plug on the receiver / dryer, set your multimeter to the circuit test position - this is where you place the multimeter leads together and you will hear a beep, or the meter needle moves across the scale to indicate a short circuit.
If placing the leads across the Receiver Dryer indicates a short then you have a full load of refrigerant gas - in your case it means the fault is electrical - if so follow terry's advice ....
The Condensor is on the outer side of the radiator, at the very front of the car.

Let me know if you need any wiring schematics ................ or a highlighting pen! - BTW Terry, thats exactly what I used to tell everyone to do, you can never mess up that way :lol:

marcusus · Postby **marcusus** » Sun Nov 23, 2008 11:43 am

@ the highlighter. I do it for work as well, but that's only when there's no one else to do it for me

Usually I don't need to do any line testing, and usually the stuff at work is a hell of a lot simpler than a car's electrical system.

So how do I get to the condensor? Do I need to just shove my hand in through the mouth of the nose (:lol: that sounds a bit odd)? Or is there a way I can get to it from the engine side of the radiator?

I'll give the suggestions another shot today if the rain stops or I can get it in the garage and see how I go.

Postby **Okibi** » Sun Nov 23, 2008 12:56 pm

MX5CHIC can you please review all that great advice you typed in page 1 of this thread, make any changes you think are necessary and either

e-mail it to me webmaster@mx5cartalk.com I will add it to the tech archives.
OR
http://mx5cartalk.com/phpBB-3.0.2/viewforum.php?f=76

I could also take a few photos.,

MX5CHIC · Postby **MX5CHIC** » Sun Nov 23, 2008 1:26 pm

You can access the condensor "through the mouth" as you said - if you have a grille, that would need to be removed first.
On your NB the gas connections are located on the sides - you cannot miss them as you can see the tubes. Use a good bright torch, all you are looking for is something like an oily stain indicating a leak. A leak can be anywhere on the system but is far more likely on the condensor through stone damage or on any connection point.
Sometimes a dye is added to the system if a slow leak is detected or you can use an expensive Leak Detector - in your case if you suspect a leak in a particular area ; just use soapy water ... if it bubbles then you have your leak AND clean hands as well!

Okibi .... I'd be more than happy to get everything in an email, I can do photos as well

marcusus · Postby **marcusus** » Sun Nov 23, 2008 3:34 pm

tbro wrote:The plug you removed off the receiver dryer will need to be bridged, wire or split pin connecting the terminals (usually two) so basically you are bypassing the L/P switch. You don't need to start the motor, just have ignition on and when you bridge terminals the clutch on the A/C compressor will kick in, you will hear it.
If this happens then you may have low gas pressure (most likely) or faulty switch (not common).
Your next test (with the bridge wire still in place) before you can be sure you have found the fault will be to remove the wire to the compressor (plug) and check if power to plug. If so your clutch is stuffed, common if A/C is used all the time.

Right, just gave this a shot. Bridging any of the terminals seems to do nothing. Turned on the fan, set the car to 'On'. I bridged the plug together, turned on the A/C in the car and nothing happened. Bridged the terminals on the receiver dryer together and nothing happened (although nothing should've happened there).

MX5CHIC wrote:If placing the leads across the Receiver Dryer indicates a short then you have a full load of refrigerant gas - in your case it means the fault is electrical - if so follow terry's advice ....
The Condensor is on the outer side of the radiator, at the very front of the car.

I gave this a shot too. Tried to buzz out across the terminals of the receiver dryer but got nothing. Tried to buzz out across the plug but this too gave nothing (I wouldn't expect continuity here though).

I still can't quite figure out where the condensor is. I've taken out my grille and felt around for the tubing etc. I think I found the A/C tubes (they seem to run in front of the radiator, then loop back), but I couldn't find the compressor they run to. Am I right in saying that the compressor is on the passenger side of the car though? If so, I don't think I'll be able to find it without being shown. It gets awfully snug in there where the tubing runs to...

Any other suggestions guys?

Seems like the best bet is to head to the mechanic and get them to have a look at it I think... doesn't seem like it's something simple that can be fixed by the amateur.

Postby **Okibi** » Sun Nov 23, 2008 5:07 pm

MX5CHIC wrote:Okibi .... I'd be more than happy to get everything in an email, I can do photos as well

Well that makes my job easier. :mrgreen:

Thanks heaps.

MX5CHIC · Postby **MX5CHIC** » Sun Nov 23, 2008 7:50 pm

If you verified your multimeter is buzzing to indicate a closed circuit by touching the probes together, then tested the receiver / dryer which indicated an open circuit - you are definitely low on gas.
If that is the case then get your system regassed first - will cost $99 - $150 depending on where you go

marcusus · Postby **marcusus** » Sun Nov 23, 2008 9:52 pm

MX5CHIC wrote:If you verified your multimeter is buzzing to indicate a closed circuit by touching the probes together, then tested the receiver / dryer which indicated an open circuit - you are definitely low on gas.
If that is the case then get your system regassed first - will cost $99 - $150 depending on where you go

Yeah, the multimeter works fine. Of course you buzz it across the probes before you buzz it across cable

Hopefully it's just low on gas and that's it. I'll have to remember to keep running it every now and then once I've redone it.

marcusus · Postby **marcusus** » Fri Dec 05, 2008 6:51 pm

Got the air con regassed today and all seems to be running again. No doubt that was all it was, but thanks nonetheless for everyone's advice. Still learnt something, and at the end of the day, there's no point if you haven't done at least that.