A/C condenser fan not working?
 

Vehicle is an '05 3.0. This week my a/c recently started blowing significantly less cold and upon further inspection, it appears as if my condenser fan is not coming on at all. Should it come on whenever the compressor is engaged?

I just read through this thread and it seems that I am experiencing similar symptoms:

http://www.xoutpost.com/bmw-sav-foru...-question.html

Are there any specific tests I can do to test the fan? Thanks in advance-

It should, I think your fan is toasted! Search for Aux fan, you'll find info on how to test it with the scanner.

Aux fan is activated by a pressure switch on the low pressure side if the AC system. My fan began running slow when the system needed to be topped off. Once the low pressure reading was over 40psi on a 90 deg F day the fan sounded like an F4 Fantom at takeoff.

Ohh... i like those planes.

If I don't have a scanner, can I just run 12v directly to the fan to see if it works?

Or use a multimeter to verify voltage at the connector. Backprobe the wires or disconnect the plug and use clips.

Thx-

I'm seeing 3 leads in the connector. Used a multimeter and looks like one is ground, one is showing 12v, and the other some sort of micro voltage... Not sure what it should be. After some searching, I found that it sends a pulse signal. If i'm seeing voltage at the connector, can I safely assume that the fan is bad, or is the system a little more complex than that with respect to how/when it kicks in the fan? The a/c still blows relatively cold when not at a standstill. Thanks for the help, everyone-

UPDATE: Got confirmation this morning that the fan was toast from an indy shop with a GT1... Evidently you can activate it directly from the software. Ordered the fan immediately after and got it installed a couple of hours ago. All is chilly again at stoplights! :) Thanks for the replies and the insight-

Good to hear.

You might want to check the R134a pressure. When I had a reading of 30psi the center vent temp was just below 50 deg F @ 90 deg outside, getting the R134a pressure to 43 psi the center vent temp dropped to 34 deg F @ 90 deg outside. It's brutally cold now!

OBC outside temp was showing 103 F here in DFW, I was able to run low fan/recirc and the inside of the truck was COLD!

Thanks for the headsup. I'll get that checked, as well. I'm just so happy to not be sweating inside the truck! :)

My cheap little vent thermometer is showing just over 40 degrees @ 89 degrees outside. When it gets into the 90's, seems the A/C struggles a bit even with a high fan setting. I've got a big cylinder of r134a and would like to pick up some gauges to learn to read pressures and top off correctly, etc. Is it a pretty simple process to learn to use the gauges? Do they typically come with detailed instructions? Thanks-

For DIYer that never worked on an AC system, if you just want to top it off I would get a gauge that just connect to the low side of the system. Getting a full manifold gauge system that allow reading of the high side pressure could be a disaster waiting to happen since the pressure from the high side could be greater then what a can of refrigerant was orignally designed to hold. Opening the wrong valve (high side valve) can lead to the the discharge of refrigerant from the system into the can of refrigerant. That is why the new 134a system was redesign so that one can not connect a can of refrigerant to the high side, but like any idiot proof system there is always some idiots that can circumvent the idiot proof design.

Harbor Freight sells the gauge set, that's where I got mine. I used the data in the Bentley Manual to get the pressures and volumes of R134a and PAG oil. I also picked up a used Inficon Vortex AC system flusher/evacuator off e-bay for $200, that's a steal.

With a precise floor scale (to weigh the R134a and PAG oil canisters) and the tools noted above, I drained, flushed, evac'ed and recharged my system last spring. With the recommended volumes of R123a and PAG oil the pressure reading on the low side was 42psi @ 95deg F ambient.

This spring the AC was a little weak and I had a reading of 30psi, bumped it up to 43psi and the AC fan foward or the radiator began running much faster and the output at the center vent dropped to 34deg. I saw 104F here in TX yesterday, low fan/recirc had the X comfortable.