Quote:
Originally Posted by pryner
Our 99 sl center vent has started to cycle open and closed. The fan continues to run. I noticed that the cycling has started to follow acceleration indicating a possible loss of vacuum. This is the only vent that is having an issue. When I looked at the CD manual for the location of the control and how to remove the first step is to remove dash. First question is where to start troubleshooting? Any experience? Second, if the control is bad is there an easier way to get to it?
Any help is greatly appreciated.
Pete
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Pete,
There are two distribution blocks in our system; the one you mentioned and one in the engine bay, passenger side, near the firewall. The block is secured by a single screw to a panel in front of the firewall. You`ll see one vacuum line in, and around 7 out. The vacuum lines are secured by a tiny plastic MB only fitting. Remove the block and inspect the outbound lines. Cracks can be tiny, so use an eye dropper (or similar) to put several drops of water on each line where it comes out of the block. If you find the bad fitting/line, replace. If all the lines check out, the fault could be the distribution block itself. Consider replacing with a new one; they`re not terribly expensive. If the system is still under performing, then and only then inspect the block in the passenger side of the car. I believe, but not 100% sure, you can get to the block by removing the knee bolster and passenger side airbag.
Bob