A/C problem opening throttle or hills

From : logan

Q: recently the a/c my 98 dodge 1500 4x4 5.9 has began to stop blowing cold air out of the dash and begins blowing it out the defrost onto the windsheild whenever i open the throttle or climb a hill. once the throttle closes or i go over the hill the air quickly begins to come out the dash openings like it is supposed to. i know on my ford cop car the a/c shuts off whenever you open the throttle past a certain point and it is operated off of a vacuum switch somewhere. i think that is what is going on with my truck. any ideas if it is the same type switch where is it at and what does it look like. i have looked for loose vacuum lines everywhere but it might help if i knew what i was looking for... or i could be totally off base. by the way the air stays cold when it goes to the defrost mode. thanks for any help or suggestions. .

Replies:

From : nitpik

sounds like a leak in your vacuum system .. someone leave a hose off lately while doing some work under the hood damper door in your a/c box takes vacuum to hold over on the cold coil all engines lose vacuum at high throttle positions such as climbing a hill spring in damper door operator returns the door to hot coil side as you climb. finish the climb vacuum returns damper door goes full cold .. life is good. i once had jeep that had a vacuum line running under the battery .. after years of acid dripping on it it developed a hole caused the same problem you mention. dont look for the throttle cutout switch .. it didnt just start working. recently the a/c my 98 dodge 1500 4x4 5.9 has began to stop blowing cold air out of the dash and begins blowing it out the defrost onto the windsheild whenever i open the throttle or climb a hill. once the throttle closes or i go over the hill the air quickly begins to come out the dash openings like it is supposed to. i know on my ford cop car the a/c shuts off whenever you open the throttle past a certain point and it is operated off of a vacuum switch somewhere. i think that is what is going on with my truck. any ideas if it is the same type switch where is it at and what does it look like. i have looked for loose vacuum lines everywhere but it might help if i knew what i was looking for... or i could be totally off base. by the way the air stays cold when it goes to the defrost mode. thanks for any help or suggestions. .

From : clyde

on mon 19 jul 2004 170036 gmt john kunkel kunkel.j@shorts.comcast.net wrote recently the a/c my 98 dodge 1500 4x4 5.9 has began to stop blowing cold air out of the dash and begins blowing it out the defrost onto the windsheild whenever i open the throttle or climb a hill. once the throttle closes or i go over the hill the air quickly begins to come out the dash openings like it is supposed to. there is a vacuum check valve located on the right rear side of the engine that is supposed to prevent loss of vacuum during heavy throttle. it is in a tee fitting betwen the engine and firewall. there is also a replacement for the check valve available at dealers. it has the check valve plus a small plastic cannister that holds some vacuum in case of a tiny leak somewhere. put one on my dakota .. solved the problem cost is $10.00 so many garys ..so.. clyde .

From : john kunkel

recently the a/c my 98 dodge 1500 4x4 5.9 has began to stop blowing cold air out of the dash and begins blowing it out the defrost onto the windsheild whenever i open the throttle or climb a hill. once the throttle closes or i go over the hill the air quickly begins to come out the dash openings like it is supposed to. there is a vacuum check valve located on the right rear side of the engine that is supposed to prevent loss of vacuum during heavy throttle. it is in a tee fitting betwen the engine and firewall. .

From : abe

theres a vacuum line for the cruise i think that runs under the battery box on my 97. common place for a line failure because of exposure to battery acid. mine was leaking there. there are actually a couple of vacuum check valves in the system too. i found mine not to be working too well with a mityvac tool i bought. i removed each one and put a few drops of silicone lube in them. they worked much better. on mon 19 jul 2004 030955 -0400 logan lhhenderson@hotmail.com wrote recently the a/c my 98 dodge 1500 4x4 5.9 has began to stop blowing cold air out of the dash and begins blowing it out the defrost onto the windsheild whenever i open the throttle or climb a hill. once the throttle closes or i go over the hill the air quickly begins to come out the dash openings like it is supposed to. i know on my ford cop car the a/c shuts off whenever you open the throttle past a certain point and it is operated off of a vacuum switch somewhere. i think that is what is going on with my truck. any ideas if it is the same type switch where is it at and what does it look like. i have looked for loose vacuum lines everywhere but it might help if i knew what i was looking for... or i could be totally off base. by the way the air stays cold when it goes to the defrost mode. thanks for any help or suggestions. ** due to spam i no longer receive email responses to ** group postings so dont bother. .

From : logan

thanks to everyone for the helpful replies. logan .