CAD not staying engaged

[Jedeka]

My 4x4 is not staying engaged on my 94. I replaced the vacuum canister on the CAD last winter and was working fine. This year, the 4x4 will work until I go down the highway at a constant speed. I will see the light blink a few times and the 4x4 will disengage. If I let off the throttle when the light is blinking, it will stay engaged. I'm thinking I must have a vacuum leak somewhere. Am I on the right track?

 

[MagSport]

My 4x4 is not staying engaged on my 94. I replaced the vacuum canister on the CAD last winter and was working fine. This year, the 4x4 will work until I go down the highway at a constant speed. I will see the light blink a few times and the 4x4 will disengage. If I let off the throttle when the light is blinking, it will stay engaged. I'm thinking I must have a vacuum leak somewhere. Am I on the right track?

Probably so. Do your ac vent positions change by themselves sometimes by chance?

 

[dapepper9]

+1 to vacuum leak since it changes with throttle

 

[Jedeka]

MagSport, now that you say that, I think the vent position was defaulting to defrost once in a while last summer.

 

[Jimmy68]

MagSport, now that you say that, I think the vent position was defaulting to defrost once in a while last summer.

My vent does that all the time. I heard it's some vacuum pot by the wipers. My 4 wheel drive stays engaged so I don't care yet.