spamman

My AC did not get cold this season. Normally it kicks butt but right now I have no AC and it sucks. I know it could be a host of things however can someone guide me on a few tests i can do (without a shop) to hopefully ascertain the extent of repairs needed?

Basically, i turn on the system, set it to 65F in auto. It just blows whatever air temp is around me. The engine idle does not change when turned on.

Thoughts and ideas i can poke at? It is a black leather interior and can pretty toasty when driving!

I appreciate all the help you guys (and girls) have. Peace: e3

maximase86

iTrader: (24)

You could potentially be low on coolant. Do you hear any clicking from the compressor when you set the climate control?

S

spamman

When you say coolant, do you mean the refirgerant? No offense, I am just checking. I am not sure I hear any click from the compressor. I will check later on my way home. Is there a solenoid that switches making the audible "click" sound?

Snypa

iTrader: (35)

I think he is still referring to actauyl coolant that the radiator use, but it could also be the free-on thing that your low on.The system might just need to get "topped-ip".

runyun972

iTrader: (7)

did you always have cold a/c?
the last few times you used it, was the air cold or did it gradually get warmer?
do any kind of modification/maintenance on your car lately?
check all of your fuses?

spamman

I will check the radiator coolant however did not think this could cause an issue with the AC.

My car cooled well right though the summer of 2007. I do not remember any decline in cooling capacity. It just was not cool when I turned it on this spring.

The only thing I did over the cold months was fix a starting issue (bascially run a ton of heavy gage ground cables). Other than that I did not do anyting to it.

runyun972

iTrader: (7)

coolant doesnt matter, the only time it does is when you're car is overheating and the radiant heat from the radiator affects your condensors cooling ability.

when installing the ground cables.. did you cause any sparks?
possibly a blown fuse/relay. check those first

spamman

Who knows. I have ham-hands so it is possible. I will check. Other checks or voltages that can get me closer? Also, it is easy to put in refrigerant? (Let's all assume I am licensed or whatever I am supposed to be...)

runyun972

iTrader: (7)

anybody can put it in... but taking it out is another thing
and the easy way and "right" way are both pretty simple

spamman

I checked the fuses and relays in the dash and under the hood. All fuses had continuity and I replaced the relay with a similar horn one and still no luck. I have no click when the AC is set for 65F. Also, no change in idle or engine sound when heated up. Whats next folks? Thanks: e3

S14-NEO

if you have AUTO AIR which i think you said you did, then you might want to try a thermistor...its located inside the evaporator box

spamman

OK, dumb question, I do have the auto climate control system. When i hit auto and set temp to 65, it does not cool, so where is the evaporator box and is there more than 1 thermistor to look at? Is there a way to test the thermistor?

Nopike

iTrader: (2)

I'm looking in FSM it states turn the AC on with FAN on high, if air flow comes from vents, which apparently yours does. You should check if the compressor is kicking in.
If compressor is not kicking in it states to check the tension of the belts to the compressor. If belt tension appears to be OK, not loose or broken then check the AC refrigerant level. If level is low compressor will not turn on, you have a leak. If you refill the system, you can get a kit at autozone, there is a good chance it will leak out again. Than you have to find out where the leak is. They sell leak test kits at autozone also.

S14-NEO

should be only one...will have three wires on it..one red, one black and one white...i replace these sensors all the time too.. check the FSM , i am pretty sure you can test it with an ohm meter to see if its any good...chances are its not...but an evaporator is not too far out of the question either...good rule of thumb, "if you dont use it, then your gonna lose it"..meaning if you havent used your AC in a while then the seals can dry out and leak refrigerant..how long has it been since you last used it?the thermistor connector can be seen by removing the glovebox...it should be plainly visable (white plug)to the left on the black evaporator box.

z00york145

you should try to recharge it with that freon stuff, maybe you have a leak in your a/c or something.

Nopike

iTrader: (2)

More than likely you refrigerant leaked out so the compressor will not turn on. If you refill it, it may work for a short time. But unless the leak in the system is very small you will probably lose your refrigerant again. In that case until you find the leak and seal it the system will not work. If you have lost your refrigerant and have a leak you will probably need a pro with the right equipment to repair it. If you want to save some money try and find/fix the leak yourself, and then take it to a pro to evacuate and recharge the system.

Nopike

iTrader: (2)

FSM states if air is not flowing normally from vents than you may have blower motor or evaperator issues. If air is flowing forcefully when set on high than you probably lost refrigerant.

S14-NEO

a word of caution, charging a system that is already fill is a bad idea..it can make matters worse. the only way to really tell if the system is fully charged is to remove it with a A/C machine and weigh it.. if you overcharge it you can blow the refrigerant out of the compressor overflow valve. if you have never heard that before it WILL scare the **** out of you and you will think you blew your car up..lol. ive seen people do that and i wished i had a camera cause their reaction was priceless..lmao

S14-NEO

a word of caution, charging a system that is already fill is a bad idea..it can make matters worse. the only way to really tell if the system is fully charged is to remove it with a A/C machine and weigh it.. if you overcharge it you can blow the refrigerant out of the compressor overflow valve. if you have never heard that before it WILL scare the **** out of you and you will think you blew your car up..lol. ive seen people do that and i wished i had a camera cause their reaction was priceless..lmao

S14-NEO

what?!?!..the force of air coming from the vents has absoultely nothing to do with the amount of freon in the system..the freon only adds a cooling agent to the evaporator in which the blower motor blows air through it.

Nopike

iTrader: (2)

Agree, the FSM instructs you to determine if this is a blower airflow issue or a refrigerant issue. I the blower motor is working normally it is probably a problem with the compressor/refrigerant level. If the blower motor is not working normally then that may be why no cooling occurs and it needs to be repaired.

S14-NEO

i hear ya, but with an AUTO A/C control head it requires a signal from the thermistor to engage the compressor..its best to cheak all the signals required to engage the compressor before you go adding freon, unless of course youve got the machine to remove it and weigh it

Nopike

iTrader: (2)

Just wondering, I also have auto AC, can't you turn the AC on manual mode? If blower motor works fine then it's refrigerant level/compressor issue?

Nopike

iTrader: (2)

Odds he has a leak and lost refrigerant 80% Odds it's something else 20%. Does not hurt to do some checking but probably will need a pro with the right equipment. He should be able to check if he has any high side pressure at all.

S14-NEO

no, it still needs a signal from the thermistor to engage the compressor clutch

S14-NEO

a refrigerant lost is possible, but i wouldnt throw all my eggs into that basket...best to check everything and make repairs accordingly

maximase86

iTrader: (24)

Sorry, I did meant refrigerant not coolant.

S

Nopike

iTrader: (2)

Just stating the troubleshooting instructions in the FSM. Maybe I missed something.

S14-NEO

keep in mind, there are two different sections in the FSM, one is for manuall air and the other is for auto air.

Mad Medicine

do you see if the compressor clutch engages? check the front part of the pulley, if it turns along with the pulley, then you have power all the way to compressor, if not what you can do is hook up a seambeam (old car lamp) to the connector of the compressor and turn on the A/C. if the light turns on, then you've got power all the way to the compressor, if not you have a blown fuse, bad wiring, or bad pressure (either too high, too low, haven't checked the fsm if maxima's have both high and low pressure switches)

basically these switches are wired up in series, and turn off the compressor when pressures fall out of spec (either no coolant and not risk burning out the compressor, or too much pressure which could rupture if the compressor keeps working.)

basically its one of those things were you open up the manual find where the problem is.

SVI30

Although this thread is mainly about replacing the compressor, there is a wealth of info in it:

http://forums.maxima.org/4th-generat...yesterday.html

Turbobink

iTrader: (2)

for what it's worth... my compressor will not cycle on. i've been told that i've somehow lost the ground circuit b/t the a/c compressor and the ECU which translates into my needing a new/used ECU.

matty

iTrader: (54)

What are the symtoms of a bad thermister ??

Crusher103

iTrader: (10)

Alot of people in this thread dont have a clue about ACs or what they are talking about, make this easy on Urself go to a shop u trust around town most places that change tires do ACs and ask them to take a look at it, report back when u get the answer, then we can help.



just being honest seriously

eclypsecl

iTrader: (2)

My car air conditioner "condenser" blew and all the refrigerant (blue gas) came out and I thought my car exploded. The air would no longer get cold (auto climate control). The idle would still jump a bit when ac engaged but blew normal air in..if you don't hear it click then it's something with the compressor or wiring imho.

spamman

Its unlikely I will bring it to a shop. I am not going to have a shop fix it. if it costs me more than $50 to get my AC back and running then I wil leave it dead. Job cut in pay is killing me so I am on my own here.

arrocha87

you wanna trade your leather for my cloth seats? lol i dont have a/c but i need a condenser, dryer, o-rings, and a pro fill by weight of freon so im looking at a few hundred bucks.

matty

iTrader: (54)

Anyone ??

SVI30

Matty, There are three in the A/C system, one in the nose for the ambient temp (#1), one just after the evaporator (#2) to check the effectiveness of the thermal side, then a 3rd (#3) in the control panel to check the interior temp.

Each one would act differently. I think thew sun load sensor only turn the fan on a notch or two up but the thermistors are the main control of the fan action.

Mainly the controller looks at temp delta to decide what to do. For instance, the inside and outside temp (#1 & #3) delta is large, it tells to fan to stay low. When the Evap is cold and interior is hot (#3 & #2), then it tells the fan to go high.

The thermal side (compressor/condensor,evap) is controlled by pressure delta between the high side and low side. When the pressure delta gets high, the compressor stroke increase to get more cooling. So there is no electrical control except the triple pressure switch which is a safety device.

I think you can check the thermistors by sub'ing a resistor of different value by look it up in the FSM for the temp vs value or dip it in hot water to see if the value changes.

matty

iTrader: (54)

Could the A/C not be pumping cold if one of these is bad ?? Its cold, but not cold cold