Climate Control Issue

[99BonnevilleSE]

Okay so this is on my 1996 SSEi. When I first start up the car the temperature will flash for a little while. About 75% of the time the heat will work, the other 25% blows cold. If i turn off the car and turn it back on it blows heat instantly. The temperature will not change as well. Heat works if connected. AC works in the summer when I by passed the heater core. And no it also wont change levels either. Its stuck in floor/defrost mode. Even if the ECC says otherwise. I'm thinking it's maybe the ECC unit itself, but not sure. Any input would be great, thanks!

[MattStrike]

ECC unit is probably easier to change out, but I'd be suspecting a failed airmix actuator and vacuum line leaks.

[99BonnevilleSE]

Well that's gonna require me taking the dash off.... Looks like it's a problem I'm addressing in the summer. Lol. In the meantime I'll hit up a junkyard soon and try to swap out the ecc unit because why not. You know what years will work by any chance? Mine is the one where you can change the mode.

[99BonnevilleSE]

Well that's gonna require me taking the dash off.... Looks like it's a problem I'm addressing in the summer. Lol. In the meantime I'll hit up a junkyard soon and try to swap out the ecc unit because why not. You know what years will work by any chance? Mine is the one where you can change the mode.

[GotBonneBWitMe]

You're safe with a 96 - 99 ECC of course.

Ive seen the 92 - 95 and I believe they are the same as well, unless the connecting pins are different. But I wouldn't think so . . they didn't change that much interior/electronic wise between those years. So any ECC from 92 - 99 will be fine.

[Sirius]

92, 93, (and maybe 94?) will fit your car but you will lose the ability to direct where the air blows. Those ECC heads do it for you and you can't change it. On the up side, if you get one of those versions you can read out any error codes it may have. With your current unit you cannot - I believe you have to take it to a dealer for that. You might consider doing that, it could give you some clues where to look for your problem.

[MattStrike]

I did not have to take the dash off on the '93 to get at the airmix actuator. I think you can just pop the lever arm off and use a wire to hold the door so it blows hot air as a temporary measure.

[Bob Dillon]

Well that's gonna require me taking the dash off.... Looks like it's a problem I'm addressing in the summer. Lol. In the meantime I'll hit up a junkyard soon and try to swap out the ecc unit because why not. You know what years will work by any chance? Mine is the one where you can change the mode.

No idea on the years, but it'll go in and out in 10 minutes. Take off the trim panel, 4 8MM bolts, out it comes and back in just as easily.

[99BonnevilleSE]

Something tells me it's not the actuator, what are the chance that the actuator broke and the thing that changes the levels broke at the same time? In all fairness it never worked right since I bought her. I have to look, I might have a 92-95 one laying around in my garage somewhere from when I parted out the old 94's. The code idea is definitely good. I've took out a ECC before so I know how easy it is haha. Same as changing out a radio basically. I'll just have to take off the dash if that doesn't work. Because even if I replace the actuator, it still doesn't fix my level issue.

[gmman]

i have 96 SE. i had similar problem with air only blowing from floor and windshield. after ensuring that vacuum was getting from engine manifold to ECC, i discovered the rubber nipples from the ECC to the vacuum vent control lines had collapsed. there is a DIY fix for this problem described in this forum. consists of replacing vacuum nipples with plastic tubing.

GOGGLE "HOW TO REDIRECT THE COOLED AIR IN LATE MODEL GM CARS" for the DIY procedure.

[Sirius]

I agree with the comments posted. You may have more than one thing going on. I don’t think your head unit is bad (I’ve never heard of one going belly-up) and I wouldn’t change it just because it’s easy. The airmix actuator has nothing to do with where the air comes out, the vacuum & collapsed nipples mentioned would, though. If I were troubleshooting this, I think I’d probably:

1. Pull out the glovebox and attempt to move the airmix actuator arm with a screwdriver or something similar. If you can move the arm at all (without getting all Popeye on it, of course), the gear is cracked and the actuator is toast. One problem isolated.
2. If the actuator checks out good, my next step would be to access the vacuum connection on the ECC Programmer and check for the common “collapsed nipples”. If the actuator checked bad, and you would like to fix it, you’re going to be accessing this vacuum connection anyway. Probably would be a good idea to ensure you’re getting vacuum on the source line first, but it’s likely you will find a blockage at this connection.
3. If the vacuum was bad and the actuator is good, fix the vacuum problem and try out the ECC.
4. If the vacuum was bad and the actuator was bad, fix both and try out the ECC.
5. Pray that everything works now.