HVAC problem

Vinman · 11-25-2007, 01:14 PM

My car doesn't like to divert air when I switch it to head and feet or just feet..it doesn't matter if its hot or cold...though I've noticed it now that I would like to have the heat all over the car not just at the windshield or just in my face..I'm not sure what the issue could be, I replaced the blower motor resistor twice and I know thats not the problem...It's probably not even related but I just wanted to throw that out there, could this be mechanical or electrical or both? has anyone else delt with this issue?

Also, as of late my rear defroster doesn't seem to be working, there are no breaks in the wire...not that i've noticed, and I'm not sure how to check the fuse (its not a fuse but i can't remember what it is, i would like to say resistor, but I know thats not right). I really need to get my heat going..seeing how its getting pretty cold out, and last winter I had the issues with my bmr but thats all set now, i just need the system to work properly.. Thank you all for any input

P.S.. I apologize for any confusion this may cause, I'm having trouble wording it properly..Thanks again...

Vinalero · 11-25-2007, 01:38 PM

The rear defroster are bitches in the Alero. There is a module that control the defrost and the antenna in the rear window. The problem is that there is too much power going through it and the plastic connector melts in the module, making the defrost inoperative. I had to replace mine last year. The module is located between the rear window and passenger side back window, behind the interior trim. For me it was a pain to reach. Just go and get a module from a junk yard, you'll save a lot of cash.

Vinman · 12-02-2007, 01:29 AM

I was just looking closely at my rear window today, and I found that one of the wire plugs may have been a little loose, and hopefully that may solve my problem with the rear defog. there are 3 of these plugs 2 on the passenger side and 1 on the driver's, which was the one that was pretty loose. Which of these are for the defrost and which is for the antenna?

Whitetigerboi83 · 12-02-2007, 08:17 AM

very top on the passenger side is the ant. there should be two or three lines coming from it up in the black part of your window.. u still might want to pull that c pillar cover off.. take the side panel off of the seats there is a bolt down under the seat belt and slide it up and out of the grove.. after that dont just pull in the c-panel cover take a screw driver and look for the metal clips holding it and twist the screwdriver under them to get them to pop out
there is a black box under there a thick black wire going to it thats your antenna from the radio. and a wire harness clip going in the bottom. thats where it usually melts.. then two wires coming off the top one to the antenna on the window the other to the rear defrost. i have an extra box here $20 shipped if yours is bad with a extra wire on it checked in my car and it works...
now with the hvac u might have to take the center console out and check your connections to the back of the knobs (little vac tubes).. or which would suck to take the diverter box out and make sure the diverter door is still connected to the bar pull inside... how do i explain this...
when u select one of the positions on the knob be it head-head/feet-feet-defrost/feet-defrost. the diverter door gets pushed or pulled to a different position inside the box. now it may be the fact that one of your vac lines came off of a canister or the bar came off of either the canister or the door.. which would be either replace from junkyard or just reconnect .... sorry cant help u from there... and hope i help some with my long explanation

my sonoma door wont go to head/feet position because the one of the vac line canister broke off of its connection to the side of the box..

Vinman · 12-02-2007, 11:06 AM

hey thanks, I'll try it when the weather breaks...its supposed to snow today and tomorrow and its pretty cold...hopefully i can get to it this week.

Satsuriku · 12-02-2007, 12:29 PM

I'm having the same problemw ith my rear defrost at the moment but its suppose to be like +50 out on tuesday (thank god for chinooks winds) so ill look then. Thanks for the info guys!

Vinman · 12-04-2007, 06:22 AM

ok, so now i think i just noticed that the top of the rear window works when it wants to, but the rest does not. I found this out yesterday when i went to warm up the ol' ho and melt some snow, and i went to scrape the rear window, the bottom half was still icy and the top was way easier to scrape. and yes my car was running for more than 10 min, which is the time that the rear defrost takes when you first push the button. its cold as hell out there and hopefully tomorrow i can take a look at it before it snows again..

Vinman · 01-06-2008, 03:40 PM

well the weather finally broke (its about 40 or so today and for the rest of the week) and I had time to take a look at a couple of things only to find out i don't have the torx head socket to take off the seat belt, but i managed to take a couple of pics..they're not very good but i think they're of what is the module that controls the antenna/ rear defrost..my question is...is there a way to tell that its burnt out with out hooking up one of the voltage testers? also, is there another one on the driver's side?

Fyi...I've come to really hate my haynes manual...for those who don't have one...don't get it...it covers the mailbu/cutlass and ga/alero..and they're "model" car(s) are the malibu and a grand am...mostly the 'bu

I apologize for these pics being sideways..thats the only angle i could get

Vinalero · 01-06-2008, 07:10 PM

Ya that module is something to get to when you cant get the seat belt off. from what i see, i cant tell if it is burnt or not, in the first pics, those 2 cables are built in the module and they come with it. On the second pic, they both disconnect. The circular one is from the radio antenna, the other one is for power of the defroster. For me it was this one that was melted in the module.