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Old 9th June 2010, 16:04   #1
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Default Need some guidance on my Siena AC problem...

I recently acquired a Siena TD60 in Bangalore. Got a problem with AC and finding difficult to get it fixed.

Based on my observation, AC works when I start the car and blows cool air for some time (may be 20 to 30 mins). After that no cool air, just fan works.

Gave the car for a good servicing to KHT motors. Unfortunately they are not able to fix this issue. Visiting Wecool near Garuda mall and heard that some electric problem. Again, another electrician near Eegipura was not able to diagnose the problem.

Anyone came across this type of issue, any suggestions?
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Old 9th June 2010, 16:32   #2
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so the AC works for about 20 mins....
the type of malfunction you've described could be

Condenser cooling fan not working or ineffective: check if it works when the ac is on and the cooling starts to decline. also check if the condenser fins and if they're blocking air passage.

check the compressor pressure (get it done with a technician) check if the back pressure is below 35 and constant when the ac is on.

you might need to replace the receiver dryer and the expansion valve.

if all these checks do not help

check engine temp if its abnormally high, which can radiate to the condenser and reduce cooling. also pour water on the condenser from the front of the car by splashing it front front when you sense the cooling is down and see if there is a change.

stay cool.
Saud
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Old 9th June 2010, 16:37   #3
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You have to elaborate a bit more. What things did you got checked?

It could be related to pressure switch, ice on the evaporator core or a faulty thermostat/AC switch or any wiring related problem.

To check if AC is cooling when you feel the AC is not working, open up the hood and look out for two pipes coming from the firewall. One should be hot and another cold. If one of the pipe is cold then your AC is working and finding out the next problem is easy. Does the idle stays high when you feel the AC is not working?
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Old 9th June 2010, 17:59   #4
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Adding little more information -

* Engine Temp is not high.
* GAS is filled.

I drove the car to service station twice. When the car starts, it blows the cool air.
But, by the time i reach the service station, i no longer get cool air. When the service station guys check the car, they said Compressor is no longer running and need to check.

Car was left at the service station for a day and they said they fixed it. The solution was, there was some loose wires with the compressor elecctric connection which has been tightened.

And after reaching the home, AC didnt worked again. Bought the car back to service station and left it there for another day.

Again, they promptly said they are not able to identify the issue. Might be something wrong with the electrical wiring. They suspected the expansion valve but they are not 100% sure. Based on their suggestion, visited another two AC mechanics, unfortunately they had showed no intrest to check the problem.

My Car is in great condition except this AC issue. Im trying to visit few more AC mechanic's to get this fixed.
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Old 9th June 2010, 18:02   #5
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Quote:
Originally Posted by Randhawa View Post
To check if AC is cooling when you feel the AC is not working, open up the hood and look out for two pipes coming from the firewall. One should be hot and another cold. If one of the pipe is cold then your AC is working and finding out the next problem is easy.
Thanks for your response.
I will check this out tomorrow morning.


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Does the idle stays high when you feel the AC is not working?
I dont know, how to check this.
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Old 9th June 2010, 18:15   #6
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Thank you very much for your response.

Quote:
Originally Posted by msaudf View Post
Condenser cooling fan not working or ineffective: check if it works when the ac is on and the cooling starts to decline. also check if the condenser fins and if they're blocking air passage.
Please let me know, how to check this.. i will do a check in the morning. sorry to say, im totally new to this car AC.

Quote:
Originally Posted by msaudf View Post
check the compressor pressure (get it done with a technician) check if the back pressure is below 35 and constant when the ac is on.
As per the technician, compressor is not working/not getting power.
Quote:
Originally Posted by msaudf View Post
you might need to replace the receiver dryer and the expansion valve.
Im ok with the replacement, but the problem is the technician;s are not telling what is faulty or may be they are not able to identify.

Quote:
Originally Posted by msaudf View Post
check engine temp if its abnormally high, which can radiate to the condenser and reduce cooling. also pour water on the condenser from the front of the car by splashing it front front when you sense the cooling is down and see if there is a change.
On the instrument panel, temperature is fine. No issues found.
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Old 9th June 2010, 20:38   #7
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Normally with the AC off, when your car is idle the rpm will be around 800 or 900. When you switch the AC on, there will be rise in rpm. It will go up to 1000 or 1100 and the engine will feel a bit of load. So check this out and let us know.

If the gas has not leaked then you could have a electric gremlin. You should get the AC switch checked, AC relay(could be sticking) and pressure switch. In some cars the pressure switch is right on the cooling pipe in the engine bay and on some as for e.g Indigo its on the fuel pump and cost around 4k to replace. But usually if the P switch goes kaput then AC either completely switches off or cools intermittently.

There is also a thermostat near the evaporator core under the dashboard, if you have icing problem then that could also switch the ac off. AC mechanics are not showing much interest in solving your problem because they have to work to get your problem solved and less paying job. They like filling the gas the quickest way of making money. You will have to find someone who has worked on Siena's before and only that guy will be happy to work on your car.

Why dont you switch the AC on only in front of the technician so that they can check various things.
Go through one by one with checking the system to eliminate the problem.

What msaudf means is that you should check the radiator like thing in front of the radiator and see if something is blocking the air flow and when you switch on the AC, there is an auxiliary fan either in front of the radiator or at the back which switches on the moment you turn the AC on. See if that fan is working with the AC on.(when your AC is indeed cooling)



Found some info on Siena AC and seems like it has a particular problem. Have a look http://yahoo.indiacar.com/buyusedtip...iena/index.htm

The electrical system in the Siena can throw up a few surprises. The AC system, for example, is a usual culprit - the condenser fan resistance and the compressor switch can fail, thus hampering effective cooling of the interior. (Notably, though the alternators in the Unos were known to be problematic, the ones in the Siena perform without any hitch.)

Last edited by Randhawa : 9th June 2010 at 20:52.
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Old 9th June 2010, 23:01   #8
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I have same problem. I have started similar thread, but still i have no remedy. I also did not get good AC mechanic,

http://www.team-bhp.com/forum/techni...e-when-ac.html (AC clutch malfunctioning sometime when AC is ON)

* Ac works normal and suddenly it stop working and blower only blows.
* Gas is charge just before 3 weeks
* No leakage of gas, When AC compressor is working , cooling is good
* When the AC clutch not engaged and started blowing hot air, i tried pouring water on condensor and radiator, but still, the compressor clutch does not engage. So i think condensor is okay.
* all oils released from valve, while filling gas, So i think no blockage in valve.


* RPM reading is less when the AC clutch is not engaged (when AC is on).

What must be the problem? My AC mechanic said it might be sensor problem in blower cabin, but now he says e have to check valve.
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Old 9th June 2010, 23:30   #9
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I have never heard of a valve problem in a car ac in my experience but that was a decade ago. Why dont you ask your mechanic to hot wire the thermostat and see if the AC switches off again?
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Old 9th June 2010, 23:35   #10
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Without having access to the car, I can only advise on changing on some parts.

The first one that comes to mind is the 4-level pressure switch (around Rs. 300) that sits on top of the receiver dryer. This switch, if malfunctioning, incorrectly tells the ECU that the pressure in the system is too high and the compressor needs to be cut. This component should be easily accessible in the engine bay.
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Old 10th June 2010, 20:12   #11
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Thank you very much for your help and advice. I was able to find a known person who can check the electrical things on the FIAT cars. Planning to visit this weekend. Keep you posted on the updates.

Wish me good luck
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Old 10th June 2010, 22:26   #12
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Hi,
My problem is solved, I had same problem as yours. After several conclusions and confusions, an bright mechanic sorted out my problem, its an loose neutral wire.

Just spent Rs.100 for labour. I am happy now. Please try it. It may also be an problem. But not sure.
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Old 11th June 2010, 15:33   #13
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Quote:
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Hi,
My problem is solved, I had same problem as yours. After several conclusions and confusions, an bright mechanic sorted out my problem, its an loose neutral wire.
Could you please be specific? Loose loose neutral wire of which component?
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Old 11th June 2010, 22:02   #14
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the neutral wire is the Earth (body earth) which is snapped into body and its in my case. but you can cross check in your car with the mechanic. go for good mechanic, else, they will diagonise wrong fault and ask you to change this and that...at your cost.
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Old 20th August 2010, 00:48   #15
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Team,

Finally, i got my AC issue fixed.

It was an electrical issue which was identified long back but unfortunately the electricians whom i know were struggled to get this fixed.

Finally, got a contact of an electrician who works from Queen's road who get this fixed for an additional charge for his expertise.

The issue was - there was no power supply from AC relay to AC system. He did something and got it fixed.

Thanks,
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