I have an 02 4Runner that has some intermittent ac issues. When it’s working, it cools great. However, sometimes it won’t cool at all. Usually we can get it to work by turning everything off and on a few times. I am assuming the compressor is this issue, but not 100% sure. I wanted to see if I could confirm that’s the issue and if I replaced the compressor, wha else should I replace?
AC Question
- Thread starter jwkiss0
- Start date
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spartacus
Senior Member
Spin the compressor it should spin freely. Check the resistance at the electrical connector it should be between 2,5 to 5 ohms. You can also energize the connector to see if it clicks.
Low refrigerant could also be an issue. Check ac relay etc.
The sight glass diagnosis fsm
Attachments
19963.4lsr5
New member
What are your outside temps?
Do you have manual or automatic climate control?
Sent from my iPhone using Tapatalk
Do you have manual or automatic climate control?
Sent from my iPhone using Tapatalk
Outside temps are in the 70's. Manual climate control.
Thank you. I will try these things out.
96RedRunner
Senior Member
[MENTION=706150]jwkiss0[/MENTION] Your symptoms fall into the realm of filter/dryer end of life.
What does the filter/drier do? Is any way to test it?
What does the filter/drier do? Is any way to test it?
weberlukas74
New member
I’d suggest first checking the refrigerant levels and the condition of the AC belts. Also, check the AC clutch relay and the pressure switches.
Look for leaks, especially around the compressor shaft seal and connections.
Besides the compressor replacement, I’d recommend changing the receiver-dryer or accumulator and O-rings to protect the new compressor from moisture and debris. Also, you can replace the orifice tube or expansion valve (depending on your system) and flush the whole system to remove any built-up contaminants.
Look for leaks, especially around the compressor shaft seal and connections.
Besides the compressor replacement, I’d recommend changing the receiver-dryer or accumulator and O-rings to protect the new compressor from moisture and debris. Also, you can replace the orifice tube or expansion valve (depending on your system) and flush the whole system to remove any built-up contaminants.
96RedRunner
Senior Member
No easy answer to T/S your problem, best advice download FSM start reading at AC-1.
I used this chart and didn’t come up with anything. I took a few pictures and a video but can’t figure out how to post them. I was low on refrigerant again so I have a leak somewhere. Any suggestions on how to diagnose the leak? I use the AC Pro refrigerant to fill it up. Do they make one with dye to check for leaks? Is there a better solution?
Seems to me that if you can get it to work by cycling through control settings, it kinda means the refrigerant circuit is OK (compressor, drier, evaporator, etc). It points to a problem of activation.
The control unit itself? Switch/solenoid for the compressor clutch? I just fixed issues with the HVAC control valve activation cable where the AC worked, but the heater would still be running.
Replacing cable for heater control valve
Edit: Just saw your post above. I hope you find the leak.
The control unit itself? Switch/solenoid for the compressor clutch? I just fixed issues with the HVAC control valve activation cable where the AC worked, but the heater would still be running.
Replacing cable for heater control valve
Edit: Just saw your post above. I hope you find the leak.
AC Pro does make one with dye.
There's also other R134a with dye available probably cheaper.
If you use the dye you can buy a UV flashlight which might help finding the leak.
Malcolm99
Member
Does turning on the AC engage the compressor clutch, if no you likely have a leak, low refrigerant or bad pressure switch/clutch/wiring, test pressure switch buy jumping terminals, does ac clutch engage now, if yes you have a leak, usually it is the Evaporator under the dash, if so you will also need a proportioning valve and a receiver dryer, some pagg oil and 134a refrigerant after the system has been evacuated and dried under vacuum. could also be the condenser infront of the Rad among many other orings and schrader valves.
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jgue467
Senior Member
If the system is capable of "cools great" then maybe the issue is the dash control unit - they flake out rather often - guy on ebay repairs for 2 bills - you must send yours in (he repairs poor soldering in known places).
One thing I have noticed is that simply turning the temperature selector from cold to hot and back again is enough to get it cooling. The system has been flaky and I thought all the refrigerant had leaked out. I put the ac pro on it and the gauge still showed in the green. I probably have a slow leak, but maybe nothing major. Seems to be something else. When it cools, it will freeze you. When it works, it works well. Does this sound like the dash control unit?
As mentioned earlier in this thread, I would suspect either the control unit, or the HCV actuator, cable, or valve.
Pretty easy to check the HCV system. Cycle between hot/cold as you mention, and see if the HCV opens/closes consistently. You can look at the HCV on the engine bay firewall, or look at the actuator in the rear left corner of the passenger footwell.
Pretty easy to check the HCV system. Cycle between hot/cold as you mention, and see if the HCV opens/closes consistently. You can look at the HCV on the engine bay firewall, or look at the actuator in the rear left corner of the passenger footwell.
The HCV actuator near the floorboard and the cable seem to operate freely when turning the knob from cold to hot. I cycled it several times and watched the operation. I also sprayed some dry lube on it too. I also saw the cable moving in the engine bay by the firewall and its operation matched the service manual. This all seemed to operate normally. How do you know if the HCV is working? I saw the cable moving, does that mean it’s working? Any other potential issues with it?
96RedRunner
Senior Member
[MENTION=706150]jwkiss0[/MENTION] There will be a temperature difference inlet to outlet side of HCV when closed.
If not, HCV has internal issue. I/R temp gun a handy gizmo.
If not, HCV has internal issue. I/R temp gun a handy gizmo.