Fred Utz

The 2 cable control of the heater, defrost is locked up, cannot get either cable to move. Have disconnected them from the heater box. both heater box gates will manually open and close

joe_padavano

So you are saying that the cables are rusted in the sheaths? If so, remove both cables from the car. Suspend them vertically and drip silicone oil down the cable so it wicks into the sheath. This will take a few days to work through. Once the oil is infused in the sheath, slowly and gently work the cables to loosen them.

FYI, you can also by repro cables from the Chevelle vendors.

oldspackrat

Or you can buy good used ones from me.
Scott
317-727-7041

Fred Utz

Thanks, Joe and Scott, the cables seem to be working ok. The problem is the top lever which controls both the heater and the defrost won't move the defrost gate. I have been able to get to eye level from the back side and I see that the tab which screws into a post and securely holds the cable, which is necessary for the control wire inside it to push and pull through the cable, is broken. To replace it would require taking the radio out and being able to work my hand in there to put an after market clamp on the cable and get it screwed in. It's convertible and I haven't used the defrost in the 20 years I've owned it so I'm going to let it go. Thanks for all your inputs.
Fred

droldsmorland

The pack rat ought to have a used intact control head in his nest of parts?

Texas69

Hi. I have a 69 convertible which uses the same head unit as the 68. It can indeed be removed from the dash witbout taking out the radio. Is it fun? Absolutely not, but can be done. I think it involves the removal of four screws and standing on your head to see under the dash.

My defroster does not work either and never cared until I unexpectedly got caught in the rain and the windshield fogged completely after putting the top up. Now the defroster is somewhere on the wish list to fix.

droldsmorland

Pull the seats and even the console/shifter if needed and if equipped. Now you can relax with your feet up on the back seat and a pillow under your head. You might even fall asleep. Your body will thank you the next day.

cjsdad

Back when I was installing cruise controls we used small metal P clamps to lock down the carb end of the cable. The clamp is extremely secure around a plastic covered cable. I don't know if the heater/vent cables are plastic covered or just wrapped steel cables but something like this might work to secure the control end without having to replace the whole thing.