Mechanics

DODGE NEON HEATER PROBLEM

2002 Dodge Neon • 22,350 miles

My neon only has a problem at highway speed when I turn on the heater or air conditioner. The rpms will start jumping up and down by about 300 rpms but it is very erratic. As soon as I shut the switch off for the heater or air conditioner the problem stops. I have replaced the transmission, tcm, pcm, throttle sensor, coolant sensor, camshaft sensor, blower motor & resistor. I don't get any DTCs, I did get one with the old transmission that the output speed sensor was not grounded properly so I cleaned up the ground and the code never came back (this code came up only once and the car's rpms did surge like now but it was without the heater or air conditioner turned on). The car has low miles on it and I have only had if for 7 months. I replaced the transmission because the torque converter started whinning so figured for the cost I would replace it all. The new transmission shifts really good and I don't feel any slipping. I know it must be some kind of electrical problem since it only happens when I turn on the heater/air conditioner. I also replace the alternator with a high output version and ran a large power wire back to the battery, I have also replaced the battery but nothing has helped. Any help you could provide I would greatly appreciate it! I am tired of working on it and putting all of the money into it. I wish it would give me some DTCs but nothing has come up in the last 1500 miles. The only thing irregular I hear is the radiator fans will turn on and run for 10 seconds and shut off but this doesn't happen all the time, most common when I get home and get out of the car while it is running. Other times the fans will run constantly until the coolant cools down. I don't know what would cause the radiator fans to cycle so short. I does it with the heater and airconditoner turned off. I know the fans are supposed to run all the time when the heater and air conditioner are turned on. Please give me any advice you can - thanks, Jason
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October 31, 2012.




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