I have a 1999 Dodge van 3500 15 pass. When you turn on the air, it makes the motor run bad. It make its sluggish, loose idle and than the motor shuts off. If you turn the air off, the motor returns to its normal idle. I noticed someone installed a switch on the dash and when you turn it on, it makes a loud fan noise. I had the some freon put in the a/c, but after 5 miniutes, it was gone. I just bought this van from someone, and it is a pretty good van with the exception of the a/c. Can anyone help me please!

 

If there's no freon, then the low pressure cut-off switch keeps the compressor from running. So what's making the noise, the blower motor?

 

The previous owner may have attached an electric "pusher" fan on your A/C condensor. Take a peek thru the front grille and look for an electric fan mounted there. That could be your loud fan noise.

 

So is the fact that the compressor is not kicking on is what causing the motor to run bad when the a/c is turned on? and what would cause the freon to come out?

 

If the A/C system is not pressurized with refrigerant turning the A/C on should have no effect on the engine whatsoever. A system vacated of R134a will not allow the A/C compressor to turn on.

The only thing that should turn on is the blower motor in the HVAC plenum that creates airflow to your floor, dash and defroster vents. At best, you'll get warm air in August unless you live north of Manitoba.

You don't really need me to answer the second question, do you?

 

I had an almost identical issue years ago and it was the AC compressor that needed to be replaced.

 

Thanks for all of the post! I bought this van for my children's program, and I was just needing to know what if this could be a do-it-yourself job. I have been burned in the past with some a/c technicians, and replaced a whole system when only a few parts needed to be replaced. So bare with me!

Do anyone know where online I can find the wiring and parts specs. for a dodge van? Free

 

Also if the compressor is going bad, will it leak freon?

 

9 out of 10 times, yes. This is due to the excess side to side play in the compressor shaft. The more play there is, the harder of a time the seals have maintaining integrity.

 

Ok I have been studying this van and I have noticed that the blower fan is what they straight wired. Why would someone straight wire the blower fan? Secondly, the back vents used to blow hot air, but now they dont blow at all. I noticed today I was driving the van up a hill and the air shifted from the front vents to the floor vents, to the defroster vents and when we leveled off it went back to the front vents. What would make it do that I would also like to know what that plastic black box is under the hood on the passenger side and how do you get it off?