A couple of weeks ago I bought a 99 blazer LS 4x4.

Tonight, I was driving home from a decently long road. About 15 miles and there where NO other cars on the road, But cops left and right. So I was using my cruise control to make sure that I was not going to speed and get a ticket because that is JUST what I need.

But Im sure that the cruise control was not the problem.

Well when it was almost time for me to get off of this road I took the cruise control off. Got to the light that I make a right at and looked down at my gauges. My service engine soon light was on.

The first think that came to mind was my gas cap. Because when I went to get it smogged after I first got it. The cap failed the first time, But the guy tested it the second time and it passed.

He told me that in the future this cap might cause my service engine soon ligh to come on. So tommaro I am going to buy a new gas cap. But just in case that is not the problem I was wondering if any of you guys knew anything else that might have caused this light to go on?

Now for question two.

For my air conditioning. The third **** over, does not seem to work. for example. When I move it to defrost for the windshield. The air will still blow out of the face vents. Nothing moves inside of the dash to direct the air in the correct place. I think that this is the reason that my air conditioning is not cold.

Because it is probably just on the fan. And I cant move it for some reason. So I was wounder what could be going on that is causing this. Or is there a wire or something that is not connected to the ****.

Any help on this will be fine. I just don't want to pay money for someone to tell me something stupid that I could have actually done myself.

THANK YOU VERY MUCH...
PLEASE HELP!!!!

 

First off, welcome to the site.

On the SES light, take your truck to autozone or advanced auto parts. They will scan your truck for codes for free. On the AC/ i believe there is a selector in the dash that might be hung up, meaning that you cannot switch the vent location.

 

x2 on the gettin' the codes scanned!

On the A/C, you may have a vacuum leak in the supply tube to the HVAC head. Is the HVAC system just stuck in one mode? Pretty much all of the actuators in the dash for the HVAC system are vacuum powered. The control head just redirects the vacuum to the proper actuator(s) to set the modes. If the search function was working, you would find quite a few posts on this topic. Off hand, I cannot remember them all, nor can I remember the checks for this... Hopefully someone else can..

 

Ok I am about to go to auto zone.

But , yes the HVAC system is stuck in one mode.

But hen I turn the **** to try and switch it to a new mode. There is NO sounds at all. (besides the click for each mode). Its almost like it just turns. Shouldnt there be a noise if there was a leak in the vacume line, that shows that it is at least trying?

And Thank you Both for your help!
Chad

 

So, I just got back from autozone.

P0135 was the code that I got.
O2 censor malfunction

so I guess that was an easy fix. But I am still going to buy a gas cap because my seal pretty much is screwed.
its all rotten and there is a part that isnt there... so its almost like a 3/4 ring. So I was reading and it said that gas could be evaporating out of my tank.
So Im buying an O2 censor and a gas cap. ......... for now.

 

P0135 is a B1S1 (driver's side pre cat) heater malfunction. Typically, this is caused by a faulty sensor... Unless you have the proper tools, checking it out really isn't do-able. I would recommend that you have the folks at autozone clear the code and see if it pops back up. Then, if it does, switch the O2 sensors side to side and see if the code follows the sensor. If you find that the code follows the sensor, then replace it with a genuine AC Delco sensor. I have compared the typical Bosch (and others) against the AC Delco sensor and the Delco showed much higher activity and faster response. An O2 sensor's response and activity when new is directly related to how long they'll last.

With the HVAC, if the vacuum line is broken under the hood, you won't get any noise at the control. One thing that may happen is a faulty vacuum switch on the transfer case. This could allow transmission fluid into the vacuum system that may work it's way into the HVAC system... So I'd pull out the control head and see if the lines show signs of transmission fluid.

There are other threads that detail this type of failure better, but since the search function is broken at the moment, I cannot find them.

 

Ok. well today I went to buy a gas cap. Just for the heck of it because mine was BEAT!.
Then I used the code machine thing and found the code (like I said above).

So what I did was just bought a new sensor right away and cleared the code.

Soo far the SES light has not wen back on. But we will see.

I still need to do what you said about the AC.

But THANK YOU for all of your help!