First off - 97 Blazer LT, 4Dr, 4x4, 4.3 Vortec


Well my A/C doesnt seem like its blowing as hard as it should. it will blow out the defrost kinda but doesnt really come out of the dash vents at all..... any ideas where to start trouble shooting this issue?

 

Have you checked the vacuum lines. A friend had an old cherokee, it had a similar problem as you have described. Turns out there was a leak in one of the vacuum lines, causing a loss of pressure in the vacuum system. Air distribution is operated by vacuum diaphragms (as this is how the air distribution valves are operated) it would only blow air in the default position which was the windshield. Hope it works...

 

well what vacuum lines should I start with and where would they be located?

 

I have posted this before in more than one thread, but do not have the time to search for them...

 

Hi again, sorry for the lack of detail before, I hope this helps, and thanks to swartlkk for the diag.'s.

Its a bit of a painstaking process. Your best bet is to go somewhere like checkers auto parts and buy a vacuum gauge (to test pressure), take out the A/C control panel from behind the Instrument Panel. Then locate the Grey tube labeled (6-Vacuum Source) attach the gauge to this tube and with the engine running read off how much suction you got. If the gauge barely shows a reading or nothing at all, you have a leak in the system between here and the intake manifold (mostly within the engine compartment). If this is the case you need to trace this tube back to the intake manifold and look for any obvious signs of wear or puncture. If you suspect an area of a leak, moisten with water and soap. If you see bubbles with the engine running, thats your leak.

However, if the gauge shows a good reading (somewhere in the middle) then you should do this same process with all the other tubes connected to the A/C control panel. You should also try to operate the vacuum diaphragms by hand to diagnose if one of these is jammed up.

Good Luck!!