Tech Territory

Hey guys! I have a 2003 Nissan 350z, and I have not had any AC ever since I bought the car, and i’m thinking that it is possibly because the blender motor isn’t working correctly? but I really cannot find any videos or that much information on how to test it, or how to get to it/where it is? help?

icer5160

iTrader: (4)

Do you get any kind of Airflow through the vents? There's the blower motor box and then there's multiple blend door actuators under the dash. One actuator sits right on the blower box (controls recirculate and fresh air intake), and there should be two others mounted to the side of the heater core/evap core housing (controls which dash vents are used, defrost, front vents, and lower vents...also controls the hot & cold temp mix). Luckily, all the blend door actuators can be accessed without ripping apart the entire dash. Just hope that the rods connected to the air guide doors aren't busted. If those break, it will require the entire A/C core box to be pulled out and repaired or replaced. I've never heard about the blend doors themselves breaking on the Z33, but ya never know.

I recently did a deep cleaning on my A/C core box so I'm familiar with the dismantle process to access/replace the blend door actuators. It's not hard from a technical standpoint, but the working conditions really suck. You really gotta shove your head and arms/hands under the passenger dash to see what you're doing. It's very uncomfortable on multiple levels. Lots of sharp edges and things wanting to poke/stab you in the face, back or hands.
Cheers!
-Icer

Tech Territory

Yes, there is plenty of airflow, and the heat in the summer still works, I just cannot seem to find the issue, the clutch engages, no blown fuses, its holding pressure in the lines, maybe its the compressor??? I dont even know :/

icer5160

iTrader: (4)

If the compressor clutch is engaging and it's running without making any odd noises... and your blower fan is working without issue, then it's possible you have a blend door problem. To be safe though, I would still recommend having a shop drain the system, pull a vacuum, and re-charge the system. You could still be low on refrigerant, but not enough to trip the pressure switch and stop the clutch from engaging. If this was the case though, you would just notice poor air cooling performance, not zero cooling at all.

Another common A/C problem is a sticking or stuck expansion valve (Not terribly common on 350Zs but common in general for all A/C systems). Again this would also cause poor cooling performance or cause issues draining and recharging the system.

Have you done a temp check on the High and Low pressure lines as they enter and exit the firewall? The low pressure line should be cold if all is working in terms of refrigerant circulation. If you can confirm the evap core or low pressure line is cold, then you may have an air ducting problem or some kind of blockage which will require further investigation.
Cheers!
-Icer

BrendanDanie

Thank you for the advice sir.

eZg

iTrader: (5)

Mine is up on jack stands for lack of AC currently. In order to check temps of lines.......is this something you can feel by touch or measure with thermometer? Let run for a few minutes before checking I assume?

Great post regardless. Thanks!!

icer5160

iTrader: (4)

If you have a laser thermometer that should work, otherwise you can touch/feel. But I wouldn't check the lines right at the compressor. Inspect the lines at the firewall (where they enter the cabin).

Also, there's no point in checking lines for temperature if your AC clutch isn't engaging or the radiator/condenser fans don't turn on. You need to verify both your fans are running and the AC clutch & compressor are engaged/working. Also, make sure your blower fan in the cabin is moving air. If any one of these components is not working, then there's no point in checking line temperature. You would need to diagnose and get the compressor/condenser fan/cabin blower working 1st.

Low refrigerant will prevent the AC clutch and condenser fan(s) from running. There's a pressure switch on one of the AC lines (can't remember if it's the high or low side). This switch acts as a safety cut-off since your refrigerant doubles as the lubricant for the compressor. If you lose the oil from a leak and run the compressor it will grenade itself in short order. If you suspect this is your issue, then as a quick test, you can turn on the AC from the cabin, and jump the harness plug at the AC pressure switch (Note: Don't leave it running for more than a few seconds). If you jump those pins (should only be 2), and the clutch and fans immediately kick on, then you either have a bad pressure switch or are extremely low on refrigerant. It's almost always a low refrigerant issue. If jumping the pressure switch plug doesn't do anything, then the problem could be a bad relay or fuse or some other electrical related issue (bad wiring, bad ac control unit, etc).

Finding the source of a leak involves the use of UV dye, a UV flash light, and evacuating then re-charging the system (not in this order). But probably the most common locations of leaks are at the condenser and the expansion valve.

Worst case scenario, the compressor is shot. Either the seals are worn out on it, the clutch or solenoid is bad, or the shaft bearings are toast. Regardless of failure mode, if the compressor is the problem, then it's time to replace the entire system. Most professional shops and the parts companies will NOT warranty an AC compressor (for good reason) if you don't also replace the condenser, receiver/dryer, and expansion valve. So be prepared to spend some cash if your compressor goes out.

Alternate worst case scenario, the evaporator core in the dash has a major leak. If this happens to you, the only fix is to replace the evaporator core. On 350Zs this can be done without ripping apart the entire dash, but it's still not a fun or easy job. In most vehicles, this is not the case and the entire dash would have to be removed to get to the heater/evap core box. This is serious work and can cost over $1k due to the labor. If it's an older car, plastic panels and snap-tabs often break, it's not fun at all.
Cheers!
-Icer

eZg

iTrader: (5)

Thanks Icer!

Jacked up front of car to see if Turbo system had eaten into the lines and check for loose connections. and felt the Lines near the firewall. Did feel cooler AND was blowing somewhat cooler air. Fans are both functioning. Would this indicate sticking purge valve since it suddenly started working?

Tech Territory

Okay, thanks so much for all of that, I am definitly a newbie with cars in general, so is there a possibility that you could maybe walk me through how to do some of that stuff? this is my first car and I am 16... thanks!

icer5160

iTrader: (4)

Hi eZg,

Not necessarily. If the system is working intermittently, it could mean low freon/refrigerant, a failing AC clutch at the compressor, or a bad AC pressure switch. Blockages can also occur in the condenser, evap core, or AC lines themselves. If the receiver dryer is contaminated with moisture or there's any moisture in the system at all, this will seriously impact and degrade cooling performance. Best practice is to replace the receiver/dryer anytime the lines are opened to atmosphere and also note, ALL AC systems leak a small amount of refrigerant over time. They are not perfectly sealed, so it's not uncommon to just need a simple recharge and be done. Assuming no cracks in the hard lines or condenser/evap core, then the AC line leak rate can be slowed significantly by replacing the old/original O-ring seals with the updated green seals (work great).

As an example for intermittent AC issues. I have a 2008 Acura RDX for the wife (family car). Honda ACs are notorious for having issues. In this case the vehicle was both losing refrigerant (leak) and the AC clutch was engaging intermittently. I had the AC recharged and all seemed well for a time, but just 5-6 months later the AC was no longer functioning or it would work sometimes (like on a cold start), but then after driving for a bit, parking to run an errand, jump back in the car to leave, and bam, no more AC. Ultimately, the problem was the AC clutch being worn out of spec, much like your drivetrain clutch, AC clutches do wear down over time and can begin to slip or fail to engage completely. In the end I replaced the entire AC system (except for the evap core). It's cheaper to replace the entire compressor vs. just the clutch (due to labor) and if you replace the compressor, then you also need to replace the condenser, receiver dryer, and expansion valve to qualify for mfg. warranty. I never did discover the source of the leak, but I'm guessing it was either the expansion valve or just bad O-ring seals.

Now I don't have a fancy refrigerant evacuation or recharge system, so I had to pay a shop to handle the work. Freon isn't healthy to breath in so avoid opening up lines that are holding a charge and avoid skin contact with residual fluid if the system has been evacuated.

In rare cases you could have a bad fuse or relay for the AC clutch or Fans. These are simple items to test/troubleshoot at home before taking the car into a pro for a recharge or diagnosis.

Cheers!
-Icer

icer5160

iTrader: (4)

Hey Tech,

This video may help. It helped me figure out how to gain access to the evaporator core box for a deep cleaning. The process he outlines in the vid gets you to the blend door actuators mounted to the cover. Watch the entire vid, some good tips in it.
Cheers!
-Icer

Edit: Don't do what he did and disconnect AC lines if they're holding a charge. I'm guessing the system wasn't evacuated when he disconnected the lines, but I'm willing to give him the benefit of the doubt and say maybe the refrigerant had all leaked out already.

Tech Territory

Okay thanks so much, I appreciate how much you've helped, ill let you know how it goes