Expert: Paul Evans/ www.chillywillys.org - 3/19/2011

Question
QUESTION: Hello,

As mentioned above, I have a 2007 Dodge Ram 1500 Hemi with an A/C problem.  When I first start it and drive the A/C is cold as ice.  If I stay parked or at a stop light, or in a traffic jam the A/C warms up and blows hot air.  It actually puts moisture or condensation on the automatic gear shift.  Once I start moving, it cools back down like ice.  I also noticed yesterday while I was getting my truck washed in one of those automated car washes (I was stopped and the A/C was blowing hot air) that when the attendant was spraying the bugs off my grill before I entered that while he was spraying water in and on the grill the A/C started blowing cold.  As soon as he stopped it blew hot air again.  Once I exited the car wash and starting moving again, the air of course got cold again.  I'm on a budget and I'm hoping for an easy fix versus taking it to the dealer.  I live in TX and it's about to get hot.

Any help would be greatly appreciated.

Thanks, Kevin

ANSWER: Hello
This is only a short answer as I am on the move. I will answer in full if this doesn't sort it out.
It sounds as if the ram air is passing through the condenser fins as it should when you are on the move.
When you stop the engine/condenser fan takes over drawing air through the radiator and condenser fins.
Check that this fan is running when stationary.
If it isn't this will be the answer.
There are other reasons that I can suggest but have run out of time right now.
Let me know if this fixes it or not
Thanks Paul

Part two.
The other reason could be a blockage in the system, the effect this has is to restrict the flow of gas and therefore the cooling effect.
A small restriction may go unnoticed on the move as the flow is increased with your engine speed
When stationary the gas backs up again
I can help you in locating a blockage but see how you get on with the fans first

Cheers Paul




---------- FOLLOW-UP ----------

QUESTION: I spoke to a buddy of mine who has an exact same truck but it's a 2006.  He said the small fan behind the drivers headlight should be turning when the A/C is on.  It was not.  I tapped the motor of the fan with the end of a screwdriver and it started moving and cooling.  I turned off the truck, waited awhile and restarted and the A/C fan is still working and the A/C still cooling.  If it comes back, should I have the fan / fan motor replaced?  Is there a short? Is it a sign that it is about to go out permanently?

Thanks again, Kevin

Answer
Condensers should always have a fan to cool the hot gas passing through when the vehicle is stationary
Tapping the motor would indicate that it is failing
Before you buy a new one, take off the old one and give it a good clean. Spray WD40, or your equivalent inside the motor housing, give the plug a good clean too

Condenser fans that don't work allow the hot gas to pass around the system and will send warm air in to the cabin at rest

Hope this helps
Cheers
Paul