make sure this is connected and the hose have vacuum on it, if you have vacuum the problem is under the dash, if there is no vacuum on the hose with the engine running, the problem is a cracked hose under the hood. good luck. i hope i helped and please accept my answer. thanks T-MAN
MASTER ASE CERTIFIED
10 YRS. EXP. ASE CERTIFIED SPECIALIZE IN ALL ELECTRICAL AND A/C ALSO AND ENGINE PERFORMANCE