Hello everyone!
I have a 1995 Blazer with 217, 500 miles on it. My current issues are the following:
1)The air doesn't come out of the front vents, only the defrost and lower vents.
2)When I put it in reverse, sometimes there's a short thumping sound at first.

I'd appreciate any ideas you guys have, and I look forward to becoming more a part of this forum.

Scott in Charlotte, NC

 

Here's to the thumping sound, have you ever changed out your u joints. If not just go under the truck and gran the driveshaft and try to move it up and down, side to side and if there is any play it time for some u joints

 

welcome to the show. (be sure to search around and post tech problems in the correct section)


while sgp got the u-joint point, you may also want to look @ the transmission mount. next time you put it in reverse, pay attention as to where the noist is coming from. a bad trany mount may have the trans actually hitting the floor.

as for the vents.........you sound like you have a vacuum problem. since your truck is a '95, you won't have the Auto Climate Control system (electronic) and you didn't mention if you can change the air between defrost to floor. can you hear the sound of leaking air (inside, behind the dash) when you shut your truck off? check the routing under the hood. a line may have become disconnected, or is bad from dry rot.

 

your thump could also be the TPS sensor. when you check it with a scan tool, make sure it has a linear reading....

and your vent problem sounds like a broken vacuum line. check the line behind the intake and follow it to see if theres ant cracks in it......

 

Thank you for the responses. I don't want to pay a mechanic if I can help it. Can someone tell me how, or link me to a diagram, etc of how to fix the vacuum tube issue? If it's something i can find and fix myself, obviously that's my first choice. I've already put so much money into this thing in just the last month.
Thanks!

 

Sounds like your defrister door actuator. This is the worst one to change. Get yourself a hand operated vacuum pump and disconnect the actyator. Pump it up to about 10 - 15 " Hg. and see if ot leaks down. If it does you're in for a real treat. My 94 just went bad and I'm waitint for it to cool off a little before I change it. It controls the air to the defroster and heater. and usually sits prettty high up on the left side of the under dash. I've changed some without ripping the dash apart (like the book trlls you to do but a piece of cake it isn't.

 

go to the distributor on the truck and you will see a vacuum line going over it to the back of the intake. once you find that rubber hose check it and follow it for dry rot or cracks. replace as neccessary...