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AC Not Blowing Cold

does200does200Member
On my black 5S, I lost cold air when running the AC and trying to figure if it is electrical or not and maybe the compressor isn't getting juice. The standard Pantera manual says relays should be on the left side of the car by the door, but of course no panel is on the left side to open since my car has been modified, and looking around under the dash I have not found any relays yet. But reading the manual, it also says fuse 7 operates the AC compressor, and this fuse looks ok just by appearance. The fan runs well, but within 2 weeks I lost all cool air. When turning the switch for to operate the AC, I don't really hear anything (such as a little load on the engine, or any dash volt meter change). This is why I figure it may be electrical rather than AC coolant.

Would appreciate any ideas on procedures to check the fuse, or the switch. I can't find any relay yet, so can't check that even if I wanted to. The following are some photos. On this one, it shows blue fuse in the # 7 fuse. As I mentioned this fuse looks good, but not sure how to check it. I also looked at all fuses in case something was switched around and they all look good on appearance.

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does200does200Member
quote:
Originally posted by jb1490:
Jan,

Relays are located above the passenger's foot well, behind a large black metal cover. It is held in place with one wing nut in the center.

John

Thanks John, I saw that box too (below), but can't quite get into it yet in the cramped garage, and we have some rain going on at the moment so I can't get it outside. Frowner I only know of very few women who are flexible enough to get on their back into that position in confined space, so I will wait on that box untill I can drive it outside. But how to check the fuse to see if that area is working?

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does200does200Member
Thanks for the tips. But when turing key on, the FI is so loud that it is hard to hear back there when I turn the AC switch on. If I check at the fuse with volt meeter like mentioned previousely above, should I be checking with engine running, and/or checking when turning on & off the AC? I am just trying to somehow determine if it may be the relay without getting into that relay box. Thanks.
dave2811dave2811Member
Jan, you have to start with the basics, and verify if the compressor is turning when you engage the system. This is a visual check by removing the bulkhead cover or observing the front of the compressor from some other vantage point.

The belt will always be turning the pulley regardless of how the system is performing, what you are looking for is the front compressor plate / clutch. If the clutch is stationary, then something has disabled the system. If the clutch is turning, then you have probably lost refrigerant or the condenser fan is not turning.

If the clutch is not turning, then you might have also lost refrigerant and the low pressure switch prevents the compressor from engaging. From here, you need a pressure test of the system.

The most likely diagnosis is you have lost refrigerant from a leak.
does200does200Member
Checked the AC fuse with volt meter and test light and it has juice, plus I tried the horn to wake the neighbors and the horn works too (which mentioned above, operates from that fuse too). Also, was able to shut it down and keep the key on so that I don't hear the loud FI system, and I turned on and off the AC knob but did not hear any click in the engine bay. I tried the same technique on my group 4 just to see if I would hear anything back there, and when doing it in that car I could definately hear a loud click in the engine bay when truning the AC switch. So, maybe the relay to check next by replacing it? I suppose when I open that relay/wire box I will see all kinds of relays, so maybe just guess which one? I decided to check all the fuses on the fuse panel too, and not all of them light up with the test light (not sure if they are supposed to or not, or maybe just when using that item for the fuse). Did not want to get into the bulkhead if I don't need to for a visual. I don't think it is the refergerant because I had such cold air just a couple weeks ago, and now suddently just warm air.
J jb1490Member
Jan,

Only fuses 7, 8, & 9 will be hot without the key on and without any switches on.

Check fuse #10 (key on). If that checks good, check for voltage on the brown wire at the A/C switch (key on). If that checks good, then turn on the A/C switch and check for power at the white/black wire on the back of the A/C switch.

Does the condenser fan run when the A/C switch is turned on (key on)?

If you have to get into the relays, the compressor clutch relay should have yellow/black and green wires (plus two other wires). The condenser fan relay should have red and light blue/black wires (plus two other wires).

John
does200does200Member
quote:
Originally posted by jb1490:
Jan,

Only fuses 7, 8, & 9 will be hot without the key on and without any switches on.

Check fuse #10 (key on). If that checks good, check for voltage on the brown wire at the A/C switch (key on). If that checks good, then turn on the A/C switch and check for power at the white/black wire on the back of the A/C switch.

Does the condenser fan run when the A/C switch is turned on (key on)?

If you have to get into the relays, the compressor clutch relay should have yellow/black and green wires (plus two other wires). The condenser fan relay should have red and light blue/black wires (plus two other wires).

John


Thanks John. I am not home now, but will check next week. When checking that brown wire and then white wire on the AC switch, should I just pull back on the connnection of those wires just enough to touch the meter test prong at those prongs with wires still connnected? I assume when doing so, the other prong of the meter goes to ground. Thanks.
J jb1490Member
quote:
When checking that brown wire and then white wire on the AC switch, should I just pull back on the connnection of those wires just enough to touch the meter test prong at those prongs with wires still connnected?


Yes, keep the wires connected to the switch.


quote:
I assume when doing so, the other prong of the meter goes to ground. Thanks.


Yes, the other meter probe goes to ground.

John
does200does200Member
quote:
Originally posted by jb1490:
Jan,

check for voltage on the brown wire at the A/C switch (key on). If that checks good, then turn on the A/C switch and check for power at the white/black wire on the back of the A/C switch.

John

# 10 fuse lights up with test light. Then I checked the brown wire at the switch with a test light, car running and AC off, and no juice on the test light. Then tested the white wire same way but with AC on and no juice on the test light. Tested the test light too, and I know that works Smiler. What do you think all that means? Maybe go after the relay next?
Last edited by does200
does200does200Member
quote:
Originally posted by jb1490:
The brown wire comes directly from the fuse panel. You may have a bad connection there. Does the heater/AC blower motor run? It is fed from fuse #10 via a second brown wire.

John

Yes, the air blows but just not cold. I will look again tomorrow closer at the fuse box for a brown wire, but I don't see it in the photo I took (number 10 fuse is the blue one on the left of the photo). Checking my photo on page one, I do see a brown wire way back there. What if I attached a aligator clip to a wire and placed it on the prong on fuse 10, and the other end of the wire had a female clip and placed it where the brown wire is on the switch and then see if the AC works? Would that be a way to at least test it?

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does200does200Member
quote:
Originally posted by jb1490:
quote:
What if I attached a aligator clip to a wire and placed it on the prong on fuse 10, and the other end of the wire had a female clip and placed it where the brown wire is on the switch and then see if the AC works? Would that be a way to at least test it?


Yes, try that.

John

Yep, connecting as described through a seperate wire from AC switch to #10 fuse prong, I could hear the compressor click in the engine compartment. There was a wire at a second level down under that #10 fuse, but was grey. Now what do you think? Not knowing about electrics maybe I need to get into that relay box under the glove box? Maybe that grey wire from fuse 10 connects to the brown wire at the relay or something?
J jb1490Member
Jan,

The gray wire should be on fuse #11. Fuse #10 should have one red/black, and two brown wires. One of those brown wires goes to the AC switch, and the other brown wire goes to the blower switch. This is on original (unmolested) wiring. There are three terminals (male spade) connected to fuse #10. They are all stacked one above the other.

John
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