If it's not the blend door here's info. from the Helms Service manual for a 93.

1) Check coolant level.
2) Start engine and allow it to reach normal operating temp.
3) Set temp. to max. heat.
4) Set blower to high
5) Select any mode except off.
6) Place hand close to lower heater hose but don't touch it because it's extremely hot.
7) Place hand close to upper hose. It should be cooler.

If both hoses are hot and about the same temp. check for restrictions in heater core or hoses or pipes.

If you know some one that has a no contact laser temperature gun it would be the perfect tool to check the temp. of each hose.

If you think the heater core is clogged, just remove the two hoses and use a garden hose in one of the pipes and see if you get good flow out of the other pipe.

You can also disconnect the negative battery cable for a couple of seconds then reconnect it. Turn the ignition switch to run (don't start the engine). The HVAC system will go thru a recalibration of the blend door.

You should beable to hear the blend door motor moving from one extreme to the other. After about 15 seconds the blower motor will come on indicating the procedure is done.

Successful completion of the calibration will tell you that the motor and motor feed back circuit are working but not if you have a broken linkage at the door blend flap.

I take it from your response you all ready have verified the blend door is moving but it still could be out of calibration. My guess is you are low on coolant, have air in the system or the heater core is plugged.

 

While we are on the subject of no heat. The motor was working on and off. When it worked, I had heat. I replaced the motor so that works fine, but now no heat. I had the HC flushed. Strange, time goes by so fast I can't remember if it was this past fall or the year before. Manual HVAC on a 95. I thought about low coolant, but wouldn't the low coolant light come on if it was low enough as to not produce heat?

 

Move to Australia. Its warm here all year round, youll never need a heater again.

 

I swear, I cannot think of Austraila, without picturing some kind of crazy scene from the Mad Max movies.

Awesome country though, one day I'll get over there and experience it firsthand.

 

No worries mate, drop in for a few drinks if you make it around my way

 

I was looking for a cheaper fix.

Oh well, spring is coming now. I guess I'll worry about it in the fall.

 

Send me a ticket.. and a cargo container for the vette and Im on my way...

 

seriously though.. neither me.. nor my mechanic can fix it and MOJO well he is just no help.. Im going to suck it up and bring it to the dealer on Tuesday.. I just hope they dont rake me over the coals!!!

 

Sounds like a backwards deal to me, what do i get out of this?

 

A fellow vette lover and a nice bright aqua c4 convertible

 

1. Melbourne is cold in winter - our summer - at least when I was there one August, so living North of Sydney, such as in Brisbane might fit the bill - but driving on the other side of the road is much more difficult to get accustomed to and if you have to have your Vette converted to right hand drive, a tad more expensive than fixing the heater.

2. Assuming you've verified that the temp door is working, then something is obstructing flow through the core. How a mechanic could not figure that out eludes me, but you might want to try another flush. Otherwise, replacing the core involves taking off a lot of parts until it's readily accessible - at least for me - and the Dealer Flat Rate is probably going to reflect that.

 

How did you verify that the temp door is moving?

Bring the car over and I'll work on it. It's going to be near 90 for the next several days....come down and warm-up....alot closer that Assuy land though...and you can drive your Corvette....no water to go over.

LannyL81

 

Thats a tall order!! We have a shortage of them here i guess (and between 3,000 and 5,000 Corvettes of all generations in this whole country), but its not going to make my car go any faster if i buy you a ticket is it!!!

 

Chris Petris addressed this problem with a '90 coupe in April '07 Corvette Fever. He says the electronic A/C control systems get confused & lose memory. His fix is to remove the courtesy fuse so the A/C programmer loses it's memory for a few minutes & then reinstall the courtesy fuse. He also says you'll have to reset the radio. He goes on to say if this doesn't work then probably need to replace the temperature blend door actuator per the factory service manual. Good Luck!

 

OK.. Tech just called ther eis a clog in the heater core.. the cost to do the job is $1000


I know this is a big job because it involves taking the whole dash out... but does this sound about right????

help!!!!

 

Horse sh*t. Flush the heater core, just drop the coolant out of the radiator, pull the heater hoses off, flush it gently backwards (as in going against the normal direction of flow), then flush forwards, then backwards again. If there is a blockage, this should loosen it up. (keep going back and forward for a couple minutes each way if its coming out with any junk or flakes)

You can do it with a garden hose. Its **** easy, and sure as sh*t isnt a grand's worth of work.

At least give that a go first. If it works, it cost you hardly anything, and you didnt drop a grand at the dealer.

 

i took it to the delaer for them to diagnose it.. they called me this am and told me its blocked.. I asked them if they tried to flush it first and they were like.. um no.. so I was like.. um do it,.

They are flushing it as we speak lets see what happens but in the event the whole thing has to go Im assuming from what I have been told that it is going to cost me that much due to the labor

 

They're not always easy to flush and system pressure is 15 psi, so going higher than that is risky. I got the one I replaced on mine cleaned out by applying 120 psi from my compressor. Of course it was replaced by then and I have no idea if I put a hole in it, but I do know that when I ran hot water through it from the tap, the sides finally got hot again.

There should be a flat rate for the core - find that and multiply by Shop Labor - usually $75 - $85/hour (I can't imagine it being more than 4 or 5 hours). If the Dealer is too high, try an a/c shop. A core is about 60 Bucks at NAPA and it'll need at least a gallon of coolant.

 

Thanks for the info.. labor rate is $93 an hour where I live.. and they want 7 hours for the job plus parts so....

 

ok its been flushed.. im on way up to get the car.. the service writer tells me that its kinda hard to notice now cause its 60+ degrees out here today but that they did the best they could with the flush and if it has to come back it has to come back