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Discussion Starter · #1 ·
Ac is not working so I did bring it in to have it fixed.
The mechanic coulnd't locate the problem.
He did the bypass test and the more.
He thinks it is the "control box" for the AC/heating.

Were is this box located? Can you test this box? how much will a new one cost?

Thanks
 

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Were is this box located? Can you test this box? how much will a new one cost?

Thanks
Well, the Control is in the dash. It has the knobs and levers that supply the signals to operate the various A/C components. Then there is the CCRM under the hood that is responsible for turning on the compressor and radiator cooling fans (as well as other things). Both have a major influence over whether and when the A/C will work.

So lets start at the begining. I want you to check some fuses. OK? Lets start with fuse #21 in the inside fuse box. We need to know for sure that this fuse is good. If this fuse is blown, you will not have power at the Cycle Switch. You have a test light....right? If not, then maybe you can borrow or buy one.

- http://www.fordforumsonline.com/forum/electrical-lighting/128-howto-check-your-fuses.html

Since your test light is ready, lets test for power at the cycle switch. Is there power at either terminal (engine running, A/C on)?

- http://www.fordforumsonline.com/for...systems/303-test-c-cycle-switch.html#post1485
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Discussion Starter · #4 ·
Tested

Ok.

The fuse is OK.
I did bypass the switch and the compressor kicked in.
With the switch bypassed I checked the pressure and is was low.
I added refrigerant untill 30PSI.
When I plugged the wires back on the swith, it did his job and the compressor kicked in again.
BUT still no cool air (I did drove a few mile to make sure)

What will be the next step?

Jurgen

PS. one of the pipes coming from the accumulator is really hot
 

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Ok.

The fuse is OK.
I did bypass the switch and the compressor kicked in.
With the switch bypassed I checked the pressure and is was low.
I added refrigerant untill 30PSI.
When I plugged the wires back on the swith, it did his job and the compressor kicked in again.
BUT still no cool air (I did drove a few mile to make sure)

What will be the next step?

Jurgen

PS. one of the pipes coming from the accumulator is really hot
How much refrigerant did you put in? Does the compressor stay running? Do you have access to gauges? We really need to know what the high side reading is before adding more refrigerant, The accumulator should not be hot, it should be cold. Are you sure the accumulator is hot? Did the radiator fan also turn on when the A/C is requested?

It sounds as if you have a leak in the system. Your A/C may have been empty. You might have air in the system.

Next step: Get gauges.
 

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Discussion Starter · #6 ·
accumulator

The accumulator self is not hot.
One of the pipe coming from (or going to) the accumulator is hot.

Ones I filled the system from about 15 psi to 30 psi I plugged the switch back up and the compressor stayed on this time.
I can get some gauges to messure the high side. How much does it need to be?
 

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Discussion Starter · #7 ·
Pressure on high side

I did messure the pressure with some good gauges.
The pressure on the high side was about 100 psi.
The low side was 65 psi (the gauge from the fill set showed 45psi)

I did fill up the system with a little more refrigerant and the back of the car get cold air now but the front is still warm air. (I don't have temp. control for the back)

Please advice.

Jurgen
 

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Hints and use of gages

If you ever doubt there is voltage going to the compressor (switch, fuse, relay), just pull the electrical connector off of the compressor, turn ac on high with car running, and measure the voltage across the wires (not connectors on the compressor). Typically you will get 12 volts if the compressor clutch is supposed to be engaged.

Trace your 134a lines to the engine firewall. Your trying to see where the evaporator (small radiator that the hot air flows through to get cold). You should find two freon (134a) lines. One is in, one it out. One should be hot, the other should be cold for a properly operating AC. The out line is the cold one and usually runs to the accumulator/dryer. Thus, the accumulator should also be cold in a properly operating AC unit.

Gage Pressures:

You really need to find what the specifications are for your exact car. It will be in the service manual. You might web search and find it. It will give you the proper ounces of charge, proper oil type, proper oil charge, and proper high and low side pressure while operating. I'm still searching for a 1997 Contour 2.0 spec, so it may be tough to find. Thus, the following will be rules of thumb.

Hook gages up. I will not go into how to do this, but will say the valved on the manifold body open the freon to the center line (yellow). Thus, keep those valves closed unless you are charging, vacuuming, flushing, or pressure testing with nitrogen through the yellow hoses. If you are charging, you will need to bleed the air out of all of the hoses before charging.

Hook gages up. Close all valves. Start engine. Slowly open low and high pressure valves at low and high pressure ports. Do not open the valves at the manifold gage set. Run engine at 1200 to 1500 rpm. Low pressure should be 25 to 35 psi (get exact number from service manual). High pressure should be about 2.2 times the temperature of the condenser. The condenser is the smaller radiator in front of the engine coolant radiator. I've got an infrared thermometer I read this temp with. The condenser temp is usually 30 to 40 degrees greater than ambient temp. Again the exact high pressure is in the service manual.

Caveat: Some people say the high side pressure should be 2.1 to 2.4 times ambient. I'm actually not sure which is right, but the condenser temp is actually closer to the freon temperature ... and that's the temperature that matters. Thus, I use the condenser temperature.

If other things are occurring or the gages give you weird readings. Low high side, but high low side pressure (etc.) then there are other problems. THe gage readings can help isolate what those problems may be.

Hope this helps.
 
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