Crazy aircon

[eau-rouge]

Cold for passenger hot for driver under normal operation..when i open vent for leg both sides are hot,cold for passenger hot for driver. I thought the heater valve kaput but it is still ok. Wonder whyControl unit out? Have you experience this prob?

 

[muhaiminrahim]

Final stage unit (FSU) aka a/c regulator.. Try check the connectors in to the FSU.. Mine functioned strangely and upon checking, i found my suppy cable was shorted to the grounding cable at the terminal.. Hope this helps:4:

 

[eau-rouge]

Fsu is for blower right? Mine is more on temperature control..i put it max 32deg but still cold as ice

 

[muhaiminrahim]

Fsu is for blower right? Mine is more on temperature control..i put it max 32deg but still cold as ice

You r rite bro.. Hmm.. Sori, cant help u here..

 

[johnj]

it has something to do with the cold hot flap which control's the temperature individually with same blower speed ( unlike e38 ). get it checked with an ac specialist.

 

[tweiboon]

Fsu is for blower right? Mine is more on temperature control..i put it max 32deg but still cold as ice

Have u use scanner to scan ur car ? Auc heating errror ?

 

[seewai]

I suspect A/C gas leakage for this case. It could be minor, which takes months or even years to have this symptom again after gas refill. It could be major, takes just weeks or even days for the "driver side hot" symtom to recur.

PS: During refill, don't put A/C gas pressure to too high, or the A/C fan would always turn at higher if not the highest speed.

Cheers,
seewai

 

[seewai]

Fsu is for blower right? Mine is more on temperature control..i put it max 32deg but still cold as ice

If heater already bypassed, you won't get heat to regulate the cold air, unless gas leaked.

Did you put the dial between the center A/C vents to three "blue"?
Try put it to center "white", and toggle temp between 16deg - 30deg again and feel if it makes a difference.

 

[Psykit]

Happened to me before, one side cold, the other side hot.

Did the heater valve delete bypass but still the same. End up refilling A/C gas and it was ok ever since. Could be a small leak somewhere but not big enough to notice. Months after the refill and still ok now.

 

[deng99]

How about this situation; when the temp set at 22c and above, front blower ok cold air, but rear hot air..when set temp to 21.5c and below then only both front and rear blower came out cold air..is it ok or ko?

 

[eau-rouge]

If heater already bypassed, you won't get heat to regulate the cold air, unless gas leaked.

Did you put the dial between the center A/C vents to three "blue"?
Try put it to center "white", and toggle temp between 16deg - 30deg again and feel if it makes a difference.

thee blue dots is set all the time..does that mean the temp dial will not work?

 

[Psykit]

Any temperature more than 16^C will trigger the water pump and the valve for hot water to increase your a/c air temperature. It's different than japanese cars where compressor will cut off once certain temperature is attained.

Always set your temperature to 16^C and a/c vents to 3 blue dots and check a/c gas first, see if pressure is alright. Start troubleshooting from cheap to expensive

 

[zulyus]

I have similar experience when bought my e39 eight months ago. The aircondman said insufficient gas and therefore he refill the gas. Problem solved and my aircond works well until today.

 

[eau-rouge]

i guess my aircon woes has solved..seems that gas is insufficient..from what the aircon guy told me, if there is less gas in system, the ac fan would not operate at normal/high speed

 

[aliris]

just a note on the aircond,

the right way to fill up freon (aircon gas) is by weight..not pressure. For pre facelift it is about 1000 g (dont remember exact figure) and for facelift model 750g. This is because our car uses variable pressure system depending on the multiple input to control the temperature.

So when you want to top up the freon, make sure the shop drain the old freon and refill the system with the right amount of gas (plus some oil ND-8 if not mistaken). refer to the a/c sticker in the engine compartment for the amount needed for your car

 

[Psykit]

just a note on the aircond,

the right way to fill up freon (aircon gas) is by weight..not pressure. For pre facelift it is about 1000 g (dont remember exact figure) and for facelift model 750g. This is because our car uses variable pressure system depending on the multiple input to control the temperature.

So when you want to top up the freon, make sure the shop drain the old freon and refill the system with the right amount of gas (plus some oil ND-8 if not mistaken). refer to the a/c sticker in the engine compartment for the amount needed for your car

Hi,

Thanks for the valuable tip, however I'm curious to know how can we measure weight of gas before filling it in? Most of the air cond technicians top up gas until the correct pressure but I'm not sure if they know to fill by weight.

Any idea?

 

[pam312]

actually those good ac shops....they hv a weighing scale to weigh the gas tank how much left....
what aliris wrote is correct....i had the same issue previously.
the AC shop actually vacummed the old gas out.....then fill up again using the weighing machine....
lately getting the same problem again....i suspect my cooling coil has some small leakage....

 

[eau-rouge]

since i topup the gas..all seems ok but....

when i switch on flow to foot area, the air is hot..upper half is alright

what seems to be the problem here?

is it normal to topup gas once a year? or is it leaking?

 

[seewai]

thee blue dots is set all the time..does that mean the temp dial will not work?

This is what happens to my ride. If you want the temp dial to work, set it to center (white bar/dot), then play around with temp, you should feel the difference, if heater has not been bypassed.

since i topup the gas..all seems ok but....

when i switch on flow to foot area, the air is hot..upper half is alright

what seems to be the problem here?

is it normal to topup gas once a year? or is it leaking?

Yeah I couldn't make cold air to flow to foot/bottom area neither, but I could live with it as I never use this option.

 

[consoglieri]

Good topic...any recommendation on good A/C servicing shops?