I've been searching the forum and can't find anyone having this issue, but if there is, sorry for another post.

Yesterday the AC started acting up, what it does is while were driving, all the sudden the AC will switch from the front vents to the defrost vents for about 20 to 30 seconds, then it will switch back to front vents. The time on front vents is anywhere from about 2-5 minutes, then it switches back to the defrost vent and so on. The air is still cold coming from the defrost vent and the front vent.

Anyone got any idea what might be causing this? Have never had this happen on any vehicle I have owned.

Thank You for any help.

 

Does it do it sitting still or is when you are accelerating? If when accelerating it sounds like a vacuum leak. check the hoses under the hood for broken lines, and check the vacuum reservoir especially if it's a metal coffee can looking thing look for rust at the bottom...

 

It does not do it while sitting in park. Where is the vacuum resevoir at?

BTW - I changed the spark plugs yesterday morning and reset the pcm, this started after that.

 

Ok, went down and looked around on passenger side, found a small hollow line crossing over the black canister that is not connected. Cannot see where it connects, will post a pic in a few if this site allows that.

 

Whew, thx for the info White, found where it connected. A black round device under the alternator. Drove it for a while and never had the problem again. Take care and have a great day!