Where is that dang low pressure fittining? I just cant seem to find it and high pressure is right up front.

 

On the side of the accumulator can, on the firewall.

 

Do I have to remove the electrical junction that covers it? Its hard to see at night

 

A 97 f-150 is not the same under the hood as my 99. I appreciate your help anyways. I didnt realize you were giving me a general answer. I know where it is on my other vehicles.

 

Look again. I gave you the specific location. It is the same as the 97.

Side, not top.... There is no electrical connection involved. Points right at the exhaust manifold.

 

My canister is buried beneath a whole lot of a electrical junction box. Is yours exposed and easy to get to?

 

You cannot see it to save your life. Stick your hand in there and feel around...SHO89 gave a good description of where it is....have bandaids ready after you find it.

 

LMAO @ buzzard

 

Found it and tried to refill. The compressor kicked in and dropped to 25 then up to 40 and bounced up and down as the compressor kicked on and off on and off...finally got it to stable at 40 on the guage but it just didnt seem right. The outside temp was 90 ish and it still wouldnt pull down past 70. The next morning the thing worked great at pulling down to 40 degrees from the vent. A few minutes later when I jumped back in and kicked it on it acted the same and only dropped down to 70 degress when it was only 70ish outside. Im losing more hair. I think ill have to dump the system and vacuum it down and start over. What do you all think?

 

Using a vaccum pump pull a deep vaccum. After the unit has sat or a while without removing the gauges check to see if the vaccum you achived is still at the same level. If there is a very minor decrease in vaccum then you don't have any leaks. If the system vaccum decreases a lot then you have a leak. At this point its best to use a flourescent dye and check your system. Make sure you check your lines to the rear A/C as well. If there is a leak, the leak must be repaired before attempting to add refrigerant.

 

A couple of points:

1: You really need a set of guages so you can monitor both the low and the high side pressures. Othewise, it's like navigating in the dark with only one eye open. You most likely will end up with a system that is either over- or under-charged with only a low-side guage. You also cannot get any diagnostic information about the operating condition of the rest of the system without both readings.

2: Low side pressures cannot be accurately measured while the refrigerant source is connected as the pressure from the container will be what is measured, not the actual suction pressure. You have to be able to turn off a valve, etc in order to isolate the container from the system and the guage.

3: A normal system will cycle (until it gets too hot/humid) the low side pressure. You should see the pressure drop into the low 20s, the compressor clutch should disengage, and the low side pressure will rise to the mid 40s. At this point, the cycling switch should close, the clutch should re-engage, and the cycle should repeat. Simultaneously, the high side pressure will rise while the compressor is engaged, and will drop off during the time the compressor is disengaged. The actual cycling time will vary greatly depending on the ambient temperature and the amount of latent heat being carried by the system from the vehicle interior to the condensor.

4: The factory service manual gives specific testing setup instructions to try to reduce the number of variables. Usually, these include engine RPM, HVAC control settings, shade, windows rolled up, etc... Your thermometer should be in the center dash vent.

It is fairly common to have blend door issues that cause HVAC system faults that may mimic problems in the pressurized system. You have to be able to identify which portion of the system is causing your symptom before jumping. Another good reason to use a manifold guage set.

Steve

 

Steve here is what I have in regards to your points
1. I have a full set of guages with both high and low
2. My can was isolated and the valve was off so I was not reading can pressure
3. The truck did just that
4. The thermostat is in the center vent
\
5. How do I check the blend door?

 

Still giving me problems. The pregnant wife and kids are not enjoying this warm weather now. AC on and now it wont pull any temps down.

How do I check the blend door? Thanks guys

 

To check the blend door you pull the actuator motor off and if pieces of plastic come out with the shaft it is a sign that the blend door is bad. If you have not checked it yet it may be the actuator motor itself.

 

Thank you Craig. Is the actuator motor buried behind the battery?