AC Issues

[scitzz]

Late model EFI. No AC originally. Guy not on this forum but on Facebook bought an AC System from Shadetree. Finished the install tonight. Holds vacuum about 27 inches of mercury for a couple hours.

Had a prior problem where the blower fan would only work on the "3" setting. After adding PAG oil, On 1 and 2 setting on the blower, the AC light on the button will illuminate, and the AC clutch engages, but it doesn't pull freon from the can. Full disclosure, this COULD be my AC manifold. It wouldn't pull freon through it the other day with a BMW.

On the "3" setting, fan blows, Ac light on the button goes out, and AC clutch disengages. Of course, it still doesn't pull freon.

The connector by the windshield washer bottle although wrapped in tape and covered in plastic sleeve from factory was still badly corroded. Used a small thin flat file, battery terminal cleaner, and multiple plugging/unplugging to try to clean as well as I could. Fuse is fine. Got too late to try another method of installing freon (used an older cheapo depot setup I still had and it worked on the BMW) but I will try that tomorrow.

Main thing is, why would it not blow on 1 or 2? Why does the light go out when the blower works? Do our cars have a heater resistor that keeps it from blowing on partial voltage when it wears out and if so, where can I get one and where is it located?

Thanks in advance. I'll be back on around lunchtime to check response.

[FestYboy]

Driver side of the blower housing holds the fan speed resistor pack. The resistive coils could be bad, or the selector switch could be faulty... As for the manifold set, did you have the high side closed and the low side open with the feed tube valve open in the can?

[scitzz]

Yes. It just started acting up the other day.

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[scitzz]

So, how about the ac dropping out when it's on the highest speed setting?

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[ryanprins13]

When it gets to the 3 setting maybe it senses there is no refridgerant and turns off the compresser. There has to be pressure in there for it to turn on. So it sounds like you need to fix the charging equipment and the blower resistor. Then im sure it will work fine.

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[skeeters_keeper]

Throw it in the trash.

[scitzz]

Throw it in the trash.

NO!

So, it pulls freon from an older rig. I am gonna have to figure out what is up with that manifold. Going to Madness Central and see if I can suss out the blower motor problems.

[1990new]

I understand your frustration very well. I'm having a hard time understanding the Air Conditioning /Heating diagram on pages 54-1 and 54-2.
After I installed the heat/air back in Rosie last year the fan would operate on 1 and 3 but not on 2. When I turn the control to 2 the blower does not run, the ac switch light goes out and the compressor turns off.
I replaced the heater resistor with a new one and it made not difference. I switch in a different heater/ac control assembly and that made not difference. In my situation, it appears there is a problem with the wire connectors under the dash somewhere. I hate to tear the dash out again to try to find where the problem is. The blower control switch also shows a connection to the PCM but only when the speed is at 2 or 3.
The diagram shows a Bl/W wire connecting to the A/C switch (The AC switch also connects to pressure switch).. this same wire connects to the BL/W wire which goes from the blower speed 1 to one of the resistor connections.
The pressure switch also connect to a wire that comes from a different source depending on whether ATX or MTX.

So it appears when blower speed is at 1 there is a direct connection to the ac pressure switch, but when the speed is at 2 or 3 this direct connection is gone and but a signal goes to the PCM which does it's magic with the AC system when it gets that signal.

Just though of something ... Rosie still has the ATX PCM in her but she is now a 5 speed I wonder if there is a signal missing somewhere that is preventing speed 2 from running?

I know this is a bit of a jumble but so is my mind regarding the AC/Heating wiring diagrams.
Wish I could be of more help regarding your overall problem.

[scitzz]

Great reading though, Jess!

I swapped in another resistor and Bob is your uncle. Everything worked. Got it down thirty five degrees at an idle. That's one in the win column.

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[1990new]

That's great news... happy to hear it. You must have the old refrigerant in that system to get that cool.

[scitzz]

Nope. Green Orings and R134A. Pag Oil with dye. Wish I could get it a little colder actually. I cleaned the heck out of the evaporator. Condenser is clean. Maybe a better/newer compressor?

[ryanprins13]

Wish I could get it a little colder actually.

I havent tried it yet unfortunatly. https://fordfestiva.com/forums/showthread.php?t=60881

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[1990new]

Nope. Green Orings and R134A. Pag Oil with dye. Wish I could get it a little colder actually. I cleaned the heck out of the evaporator. Condenser is clean. Maybe a better/newer compressor?

Good luck with that AC system lasting very long with Pag Oil if you didn't flush the system and put in new receiver/drier and new or rebuilt dry compressor.
I put Pag oil in Nellie's system when I converted here using a rebuilt compressor and it lasted a little over a year before the compressor locked up.
The rebuilt compressor was not supposed to have mineral oil in it but I'm guessing that compressor was just cleaned up and sprayed with aluminum paint and as much mineral oil that could be drained was drained but it cant' be drained completely.
When I opened the system it was full of black sludge. After that I disassembled the entire system, bought new receiver/dryer, expansion valve and new compressor and recharged with Ester and 134a. So far no problems.
I know Ester oil isn't the best but it appears to be the only one that will lubricate the system with 134a and survive when there is residual mineral oil in the system.

[scitzz]

Flushed it and used a new receiver dryer, you should always use a new dryer anytime you open the system anyway.

I filled the compressor with pag them drained it. Refilled again for install. We'll see how it goes I suppose.

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