Welcome to the Corvette Forums at the Corvette Action Center!

Ozzy from Ozzys Customs


New member
Feb 5, 2017
87 corvette C4
Hi. I have a 1987 C4 Corvette and I am having an issue with the routing of the vacuum lines both under the dash and in the engine compartment. I have replaced the motor, however I have run into an issue with wiring the motor, I have wires that do not have a place to plug into. The car runs and drives just great. I removed the smog pump and installed headers and some other add-on's. During this process I have lost vacuum to the climate control. The blower motor runs, changes speeds sensors are working but nothing works when it comes to changing from heat to defrost or A/C. Air just blows out from all vents. None of the air flow doors are moving. So I think it must be in the vacuum lines not connected properly. I also replaced the heater the heater core due to a leak. That wasn't much fun. ( But I did find a short cut to that process. you do not need to remove the entire dash, simply cut the inner part of the dash behind the radio and either pop rivet or epoxy it back together using a piece of like plastic as a back up for strength. So you do not have to remove the entire dash, which cut the time at least in half. )Then I need to know which vacuum lines I can eliminate and which ones I still need to use, and where the others need to go. Then how is the vacuum connected to the climate control through the cowl. I have a 1987 corvette service manual but it is a bit vague in this area. If you could tell me where I could find the diagram of the vacuum hose roughting and any other suggestions would be greatly appreciated.
Thank you; OZZY
Welcome to the Corvette Action Center. I'm going to move this into the C4 Tech forum for greater exposure...
Welcome To The CAC

there are some sharp C4 owners on here. I'm sure you will get the help you need.

Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors


MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!

Advertise with the Corvette Action Center!

Double Your Chances!

Our Partners

Top Bottom