81 Suburban A/c problem

Um, can you be more specific? Do you want the diagram for the HVAC vacuum tubing? The selector switch on the dash also routes the vacuum to the proper vacuum motor (diaphragm). I know the one on my mom's 83 van no longer works because it now leaks (like a sieve, luckily it is a diesel so no vacuum is necessary anywhere on the truck). So you want to pull one of the vacuum hoses off the plenum (behind the glove box) and recycle the dash selector switch to make sure the switch is routing the vacuum. If it does then the diaphragm that moves the heat/vent/defroster door may be bad. All of the diaphragms can be checked by attaching a small section of tubing (clean) and just suck a little vacuum. The diaphragm should hold the vacuum for a few seconds. If it doesn't then the diaphragm is bad. If you need the vacuum diagram let me know I can email it to you. No problems... And it isn't reaching back the same system is in my daily driver (91 suburban). Keep this in mind if you need parts any junk yard can supply anything you need for that truck, as well as JC Whitney and LMC truck for new parts.

good luck, mark

rock snipped-for-privacy@hotmail.com

the vacuum switches in Burbs are prone to fail

I need the HVAC routing. Most of the links to the tubing are dry rotted. I have went total away from factory on the engine. So I am looking for the line or where the HVAC system gets its vacuum to work. The diaframs all seem to work correctly.

Hi, I emailed you the web address to where I posted the diagram. The address unfortunately included personal information so I did not want to post it to the web. I hope it will helps.

mark

Chances are there is a pinhole leak in the diaphragm that opens or closes the intended vent, judging from the age of the vehicle this is probably the case. On the same note lets don't rule out the vacuum switch or amplifier. check for vacuum at the switch and go from there, i believe the Chiltons book for that year had the schematic you're looking for.

-- George S.