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04 Grand Marquis No A/C

4444 Views 8 Replies 4 Participants Last post by  jbrown91
Hello, I have an 04 Grand Marquis that doesn't have working A/C. I replaced the EATC because it was bad and had the common defrost/floor problem. But that didn't fix it at all. Whoever owned this car before has worked on this, they had a lead coming off the clutch cycling switch. I connected the lead to the battery, and the clutch will kick on but after a minute it will throw freon out the backside. I had gauges hooked to the low and high side, they work right at first but after that minute the pressure "builds up" and the high side jumps up high then releases it out the back. I took it to a mechanic and had it recovered, take all the freon and find a blockage, and all was fine. My friend has a Snap-on Solus and it said about the EVAP Temp. sensor and I replaced it and also the low side pressure switch to no avail. I'm not sure what else it could be, any help is much appreciated. Thanks
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Sounds like the electric fan isnt working(radiator)
I'm with Phantom. Sounds like the radiator fan is inop.
Check your fuses under the hood, specifically fuse F1.102, which brings power to the fan (red/black)
Also check for ground availability on the black wire going to the fan.
There is also a third wire on the fan motor...the signal wire (red orange).
Your cooling fan is pulse width modulated. This means the PCM is controlling when, and how much, the fan is operating. It is giving a pulsed signal to the fan.
The A/C operation is heavily influenced by the PCM, and there may be an underlying problem that is affecting both the A/C and the cooling fan.

My suggestions are
1) Check for PCM codes again.
2) Check EATC codes:
I forgot to mention, it won't turn on at all from the eatc. But only jumping it.

Would the fan cause that problem? But why doesn't the eatc turn it on?
I'll be home tomorrow to mess with it. I'll be doing it asap, it's for my dad. I'll do the eatc codes liks you said and hopefully I can get the Solus again. Thanks!
My dad tried the test and nothing popped up, assuming he did it right. The electric fan isn't observed to be on. I'll have to check it and stuff, he's looking at fuses. Would the fan keep the compressor from running?
Get a wiring diagram and do continuity tests between the EATC and the clutch coil.
I did the self test and got a

052 Sunload sensor intermittent short

What does that mean?

EDIT* So it may turn out that was from the car I pulled the EATC from.
With some help from a friend, we've narrowed it down to the PCM. We did some ohm testing and it is showing like WAY to much resistance for the EVAP temp sensor.
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