Im having ac problems
Im having ac problems
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
Does the air stop flowing out the dash vents? Does it switch to the floor or defrost? If you stop driving does the airflow return to the dash? Did this problem just start? What service was done beforehand? What model and year truck do you have?
Thread Starter
|
New User
Joined: Apr 2011
Posts: 9
Likes: 0
i have a 1992 f150 I6. the ac doesnot cut off at all. its at cold then as soon as i start driving it gets hot. the ac still blows when i drive and never cuts off. it started after winter. i have done all the services myself, just regular oil and i changed the brake lines.
Thread Starter
|
New User
Joined: Apr 2011
Posts: 9
Likes: 0
Trending Topics
Senior User
Joined: Mar 2011
Posts: 242
Likes: 0
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Logistics Pro
Joined: Mar 2005
Posts: 4,698
Likes: 47
From: Mexico, Missouri
Wild thought..perhaps the blend door is opening when driving(for whatever reason). This would allow for heat from the heater core to seep thru and give the expression the a/c wasn't working correctly.
Best idea I would suggest is to start the truck and with the a/c running and blowing cold, actuate the temp **** selector. See if there a complete motion and you can't simply pull it open when it's in the cold range.
The blend door itself could be malfunctioning or check the housing that holds the ac part near the firewall. It will be enclosed in a black 2-piece housing. It could be separating and while driving air entering the engine bay maybe blowing the housing opening and thus allowing for hot air to come in.
Best idea I would suggest is to start the truck and with the a/c running and blowing cold, actuate the temp **** selector. See if there a complete motion and you can't simply pull it open when it's in the cold range.
The blend door itself could be malfunctioning or check the housing that holds the ac part near the firewall. It will be enclosed in a black 2-piece housing. It could be separating and while driving air entering the engine bay maybe blowing the housing opening and thus allowing for hot air to come in.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
Wild thought..perhaps the blend door is opening when driving(for whatever reason). This would allow for heat from the heater core to seep thru and give the expression the a/c wasn't working correctly.
Best idea I would suggest is to start the truck and with the a/c running and blowing cold, actuate the temp **** selector. See if there a complete motion and you can't simply pull it open when it's in the cold range.
The blend door itself could be malfunctioning or check the housing that holds the ac part near the firewall. It will be enclosed in a black 2-piece housing. It could be separating and while driving air entering the engine bay maybe blowing the housing opening and thus allowing for hot air to come in.
Best idea I would suggest is to start the truck and with the a/c running and blowing cold, actuate the temp **** selector. See if there a complete motion and you can't simply pull it open when it's in the cold range.
The blend door itself could be malfunctioning or check the housing that holds the ac part near the firewall. It will be enclosed in a black 2-piece housing. It could be separating and while driving air entering the engine bay maybe blowing the housing opening and thus allowing for hot air to come in.
Great idea!
Logistics Pro
Joined: Mar 2005
Posts: 4,698
Likes: 47
From: Mexico, Missouri
If ir doesn't return to cold when stop and/or sit idle, there could be a problem with the A/C itself. After starting the truck, visually look to see if the a/c compressor clutch engages when the A/C is cycling. Drive the truck and after you notice it getting warm, stop the truck, pop the hood and look to see if the clutch is still cycling. IF the clutch isn't cycling after you have been driving, best bet is to get some gauges on it as RLA2005 stated or get it to a reputable shop so they can further diagnose the problem.
When the A/C wasn't working on my ol' '92, the shop charged me about $175 for charging, replacing 3 O-rings, and a new low pressure side switch. I thougth this wasn't to bad since it was never serviced prior to my purchasing it.
When the A/C wasn't working on my ol' '92, the shop charged me about $175 for charging, replacing 3 O-rings, and a new low pressure side switch. I thougth this wasn't to bad since it was never serviced prior to my purchasing it.
Tuned
Joined: Apr 2011
Posts: 464
Likes: 5
From: Redmond, WA USA
Another possibility that has not been mentioned yet is an open water control valve - the vacuum-operated valve that controls the flow of water through the heater core (IIRC it is vacuum applied to stay closed, no vacuum means valve is open).
The air first travels through the A/C evaporator coil, where it is cooled and dehumidified, before traveling through the heater core. If the heater core has hot coolant flowing through it, the cold air will be reheated. This is desirable when you are trying to defrost the window, but not so much when you want to cool down the cab.
And when the engine is cold, the heater core is cold also, so this could explain the cold air at first and then none after the engine warms up.
The air first travels through the A/C evaporator coil, where it is cooled and dehumidified, before traveling through the heater core. If the heater core has hot coolant flowing through it, the cold air will be reheated. This is desirable when you are trying to defrost the window, but not so much when you want to cool down the cab.
And when the engine is cold, the heater core is cold also, so this could explain the cold air at first and then none after the engine warms up.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
This vintage truck does not use a water flow valve for heater functionality. There is a temperature blend door in the plenum chamber. Perhaps you are on to something there but in different way.