I have a 96 LT1 and when you turn the air conditionere on the air comes out the floor and defrost first. First thing in the am it takes about 60 seconds before it comes out the dash and after that first time of the day then it takes 2 to 3 minutes. The dealer says it is one of the two programers. Does anyone know how to get to the programers. I am under the impression that you have to remove the dash cap. If that is true does anyone know the procedure for this...Thanks

 

Sorry I can't help but, here's a bump for you. TTT

 

There is a purge function built into electronic a/c and that helps to keep the windshield from fogging up. The dealer should have been able to test the Programmer with a Tech 2 and the right cartridge. With that, you can command the same functions that come from the Dash Controls over a serial data line and if there was no unusal delay, rule out the Programmer and replace the Dash Controller - or if it acted the same way, narrow it down to the Programmer. Trouble is, there's no published spec for how long the delay should be so the Dealer may have simply shrugged his shoulders and told you it's one or the other. In any event, the Programmer is kinda the guts of your HVAC system responding to a data stream from the Dash Panel and then controlling everything from compressor engagement, to blower speed, to the vacuum that's flowing to the HVAC solenoids. If this is a new problem, the Programmer would be the prime suspect if only because they seem to screwup more than the Dash Controls. On the other hand, you could replace it and the Dash Controls and end up with the same thing so if this isn't new, try and experience another '96 first. Otherwise the Programmer is usually mounted near the left side of the heater plenum above the accelerator.

There is another quirk with electronic a/c and that involves a relearn function when memory power is removed from the system (such as disconnecting the battery). Once repowered, the blower doesn't function and the temp door is cycled from fully open to fully closed. This allows the Programmer to learn it's position, electronically, and after about 2 or 3 minutes, everything should function normally. But, if you are seeing zilch at start up, then suspect that the memory power supply has an intermittent open. I don't think this is what you are experiencing, but I thought I'd mention it just in case.

I don't have access to complete Service Bulletins for your '96 but the only one I found was a revised diagnostic chart for the blower motor. Would hope that your Dealer checked for any and found none, but you might ask him or some are listed at www.nhtsa.gov

The only other thing you might want to check is the vacuum tank. Apply 10" of vacuum and make sure it holds.

 

Thankyou very much. Sounds like I need to go back to the dealer first and find out how they arrived at the problem being the programmer. Normally I probably wouldn't mess with it, but here in Az when it hits those 100's, the last thing you want is "slow air conditioning". Thanks again............

 

I'd guess the Dealer put his Scanner to it - A/C isn't instantaneous as it takes a couple of compression/evaporation cycles to get frosty air. In your climate, you might be able to improve it by reducing the charge a little bit (assuming it's full) - like maybe an ounce or two. You need a decent manifold gage set and a digital thermometer to monitor center vent temps, but with a little less you might feel cold air within a few less seconds at start up. Of course you don't want to go too low as then it's going to get warmer the longer it runs. A competent a/c shop could probably tweek it for you or talk to the guys at www.acsource.com or www.ackits.com - I think both outfits are in AZ and they run some really good a/c info boards.

 

Make sure you check the vaccum lines under the hood first for cracking or collapse. The vents are vaccum controlled. I had to change all of my lines.

 

every 96 has a bad programmer. 96's seem to be different from other years..

 

I had a similar problem on my 94. All the air would come out the defrost for a minute when I started the car then it would slowly switch to where it was set. Turned out to be a vacuum leak in a check salve near the fuel rail.