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Discussion Starter · #21 ·
Could be expansion valve, which to my knowledge is thematically controlled (cant say as I have seen an electronic valve) Or could be an orfice tube in which case it basically a narrowed down restriction to cause a pressure differential as refrigerant comes out the other side. Is it a manual or automatic type system. Do you set temp in controller or just have blue marks for colder. OK just looked in tech data, it expansion valve.
I do have the simple turning knob.
 

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Gauges, need to know pressures. Static and working. I cant necessarily narrow down the fan speed thing other than if its marginal on cooling, the more air you move across evap the less time said air has to cool comming across it .
 

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Discussion Starter · #23 ·
Unfortunately I don't have gauges at home- All I have is this cheapo tester with green, yellow and red scale- when it runs and cools, the low pressure line is green. when it doesn't, the low pressure line is in the red, which would indicate, the expansion valve bypass is open and lets all the pressure directly into the return line. Regardless, the fan is running and the compressor is engaged, means, the high pressure does not exceed the max and when cooling, the low pressure not the minimum.
I still think, maybe the blower motor resistor under dash might indicate a wrong signal to the what ever module responsible, which then might shut the gas flow into the evaporator down. But this would require an electronically regulated expansion valve- which would be very strange, as I know- this is a thermal-sensor regulated valve- if not otherwise- I would not wonder in today's technology, if there would be maybe an electrical bypass valve, controlled by the signal of the blower motor.
I replaced the blower motor a year ago and it acted weird after that from the beginning. I had absolutely no time to mess with it and thought I do it later- last fall, as I did it, I couldn't even get one- I found one at Autozone. Ever since, the blower cuts off on max. So I didn't put it on max, and in the winter I don't use the max anyway. I noticed the AC problem just about a month ago, as I came out after work and the truck had about 100°F inside. I turned the AC on and of course blower not on full max, but one setting below. The AC was cold and as I got out of the parking area, the blower still worked, but just hot air came out. Ever since, I tried to play with the switches and blower settings- and I found- as long as I leave it on 2, the AC works and no problem- only when I turn the blower switch on higher settings, the AC turns off and does not come on anymore- only after about 10 miles driving and blower on 2- if it's not on 2, it does not come back on at all.
That's why I think, it's the blower motor.
 

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Without a set of gauges hook up, both low & high you're like a blind man in a dark room looking for a black cat that ain't there.


Go down to Harbor Freight and buy a set, there're cheap, but they'll do Hook up BOTH sides, have someone rev the engine up to 1500 rpms turn the fan on high, stick a thermometer in the center vent. Now, if the comp. stays running, fan stays on, the ambient temp is 90 or above the pressures should be about 36 + or - on the low side and around 250+ or - on the high side. Temp coming out of the center vent should be around 50 degrees.

This is what to expect outta a fully charged system.

Now, with all that garbage being said are the pressures out of range? Like the man said could be a blockage.... most of the time its low on freon. Is the fan staying on?...like the man said...if the fan goes off the high pressure switch will take the system off line...to protect the comp.

If there is a blockage, remove the high pressure line and the accumulator. Disconnect the low pressure line at the comp. manefold . Also disconnect the high pressure line at the comp. Go down to the auto parts store and buy 3,4 cans of a/c flush, follow the instructions. Buy a new high pressure line and accumulator. Hook it all up except at both sides of the comp. Get a jug of nitrogen and blow the entire system out, remember, the comp. is not connected on both sides. Connect the comp. up and pressure the system up to 100 pounds of nitrogen. Shut off the gauges and let set and hour or 2. "If" the system was put back together, with new O rings, and the pressure holds hook up a vacuum pump and pump it down to around 28 to 29 microns and shut the pump off and let set 30 minutes. Then charge the beast up to what ever it says on the little sticker some where under the hood.

All this is "assuming" it's a 134a system.


If none of this "stuff" works take 2 aspirins , a quart of Wild Turkey, and a 6 pack of Budweiser and call me in the morning...."if" U can.


.
 

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So here's my two cents. You have a 2014. The refrigeration system is a sealed system, freon just doesn't leak out unless the o-rings have dried out for what ever reason or something has been repaired/replaced. There would be no reason to stop by your dealer and top off the Freon. Appears it needs to be serviced (freon added, measured and pressures set to factory). By you adding additional freon you possible over filled the system which would cause it to cycle on/off as you have indicated. As one posting stated recover all the freon and them recharge.

I'm confused a fan is attached to a motor, the motor turns the fan blower. So, which is it? Appears the blower motor is running then turns off, possibly the motor is going ban. Run the blower on high for a few in a vent setting in you climate control. if is runs for 30+ minutes without out shutting down, then your motor is good.

Tons of Good Advice Though, throughout the blog. Thanks
 

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So yesterday in central Fla it was like 96 when I got to barbershop. I was thinking about this thread and opened hood. Now I dunno about the 1500, but my 2500 V-8 has stupid long lines across engine bay. So even as long as they are one is still cold enough it has sweating. Still leaning towards restriction. Pressures pressures
 

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Discussion Starter · #27 ·
So here's my two cents. You have a 2014. The refrigeration system is a sealed system, freon just doesn't leak out unless the o-rings have dried out for what ever reason or something has been repaired/replaced. There would be no reason to stop by your dealer and top off the Freon. Appears it needs to be serviced (freon added, measured and pressures set to factory). By you adding additional freon you possible over filled the system which would cause it to cycle on/off as you have indicated. As one posting stated recover all the freon and them recharge.

I'm confused a fan is attached to a motor, the motor turns the fan blower. So, which is it? Appears the blower motor is running then turns off, possibly the motor is going ban. Run the blower on high for a few in a vent setting in you climate control. if is runs for 30+ minutes without out shutting down, then your motor is good.

Tons of Good Advice Though, throughout the blog. Thanks
134a is defunding through the hoses over time- you loose the gas during the years- that's why you should maintain it every 2 years (which I didn't do- I admit).
There are 2 fans- the one at the engine, which is for engine cooling. the second is an electric fan sitting right at the radiator, which comes on as additional cooling either, when it's very hot and you sit in traffic and the engine fan is not enough- or if you turn the AC on, it is additional cooling for the AC cooler. the blower motor sits under the dash. I learned now also, that the blower motor has 3 pins- one for plus, one for minus and one for the AC. there is the expansion valve, which is regulated by a thermal switch. The pressure in the system is higher as needed, to be able to supply always demand- the extra pressure is routed through a return pipe into the low pressure side.
I also found, when the additional e-fan is not running, the AC will go in bypass mode to prevent damage, as the gas would overheat.
I changed now the blower motor under the dash for an original one (the old one I got through warranty back to Autozone and got my money back- after I had to explain the guy what it means, what is written on my receipt). Now, the blower motor does not cut off anymore and has a steady speed- which was one of my concerns- every time the blower motor slowed down, the AC cut off.
Yesterday, I drove out from work, outside about 80°F and turned the AC on. What happened is, that I haven't heard the e-fan coming on, but the AC worked. On the way to the interstate (2 miles), I turned the blower up to max and after about 2 minutes, the temperature of the air got up and it smelled "moist". I kept the blower on high and went on the highway- another 5 miles driving, suddenly the air cooled down- I kept the blower on high. it stayed cold. Even after I stopped at Autozone, all the way home. At home, I drove under the car port and the e-fan was running.
This is, why I don't believe in blockage or not enough 134a- I filled this up before.
My next step will be- because it's cheap- to replace the e-fan relay, as I noticed, the air got cool as I came to an incline, the transmission switched back and the rpm went up to about 2200 rpm at about 68mph. My guess is, that maybe, the relay does not give enough power to start the fan up- through the vacuum on the backside of the e-fan, caused by the engine fan, the fan will turn and maybe this "help" is getting the e-fan going. I work with electric motors, and I see sometimes motors, which do not run- if you give them a good spin by hand, they start running. If the relay is not working, the next thing will be to check the e-fan itself. I'm pretty sure, the gas-flow system is ok, as the compressor is running and the AC is actually going after a while and stays on- so I don't believe that there is a blockage at any kind. If so, this would mean, that the compressor is about to go out- the only place, where "debris" can come from in an enclosed gas- cycle.
I keep y'all posted.
 
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