Climate control problems. 96LT-1

[vsg914]

My climate control started acting up this summer when it was 115 degrees. The AC has not blown out the dash vents in a year or so, only the floor and defrost vents. During the summer heat wave it would sometimes blow cold air, then switch to hot then back to cold. Recently, I would turn off the system when turning off the car, and when I restarted the car later it would turn itself back on and the temp would be set at 86 or higher. This went on for a few weeks, then one day the control panel started flashing and went dark. It has not worked since. The car was in the paint shop for a few weeks getting some much needed touch up and I just got it back yesterday. I haven't checked the fuses yet but "assuming" they are good, where is the next place to look? I'm thinking the control module maybe? I'll confirm the fuse are good this morning and report back on that.

Thanks in advance.

 

[vsg914]

Fuses 1 and 43 are both good. Are those the only ones that control the system?

 

[vsg914]

Well, I have the head out but I don't know if its shot or its just not getting power. Can someone tell me which wires are the ground and power on the plug? Is there a wiring diagram somewhere? Someone? Anyone?

 

[air1jpg]

Have you purchased a FSM? (Factory Service Manual from GM) If not, you can probably find on on Ebay for about $100. The service manual has invaluable diagnostic information on every system on your vette and it is model year specific. There is a button combination (in FSM) you can press to put the climate control unit into a diagnostic mode and gives you codes. Your problem could be something as simple as a bad ground connection.

 

[Hib Halverson]

You didn't say if the car has C68 or not but if it does, without the FSM, you might as well put the control head back in and take the car to a service shop familiar with C4 HVAC.

Even with manual air, if you don't have the Service Manual useful diagnosis is pretty tough.

 

[boomdriver]

without a FSM , at home troubleshooting is

Too many wires, too many shared, ecm solid state circuits, far too complex.

Like Hib & Air1 have stated, you can find used FSM sets (2 book, one dedicated to elect only) for $75-100
New for as much as $150. There are some CD versions that have some limitations that sell for much less...$50 or less.

There is a link here for the seller of new. If possible look for an older set of paper backs on e-bay. I know those still have the color elect drawings that are an exact match to your wire harness....makes life lotsssss easier.

Been told the newer editions are B&W and a bit harder to follow. hnoes

Don;t bother with a haynes to do electrical. They make good underwear but lousy repair books. Too generic and no elect to speak of. Same can be said of all the other $20 books. Most don;t make boxers or T shirts so you;d think they would make a good, valuable manual, but they don;t. Too expensive for a door stop or a table leg leveler...but thats where they end up.

Real GM FSM or find a shop.

 

[vsg914]

Update: had the hood up yesterday checking fluid levels and such, and just looking around in general, spied two wires from the ac clutch that looked pinched. Sure enough, they had slipped between the ac bracket and the cover for the asr (I think) and shorted. Replaced ac clutch fuse and it came on and functioned properly. I checked all the fuses that I thought were relevant to the system. Completely missed that one. Well, the unit is clean now anyway. There was just no way I was going to buy another one without knowing for sure this one was toast.

Looks like a fsm in is my future.

 

[boomdriver]

Glad that you got it with minimal grief...

A FSM is probably the single best "tool" that the Corvette owner will ever buy. Without these 2 books a $20,000 Snap-Off tool box is useless. (settle down.. $20K in snap-on ain;t much)

In 25 yrs of ownership, I've learned more in a few weeks with a FSM than the 20 years prior....Its an absolute must, even if you sub out repair work so you know when a shop is honest, or so you can DIY and have a chance of success. The FSM is in such great detail and the flow charts are designed to cover any possibility.Easy to follow. Its almost bubba-proof. Almost.

 

[John Robinson]

I agree with boomdriver on the value of the FSM. But I think that those of us that use it have to remember that it can be daunting to say the least to someone who has never used a service manual before. I know that I had a difficult time just figuring out how to read the darn thing. So here is my question to all the users of the FSM do you think it is possible to put together a site labeled FSM for Dummies? What we would have to do is invite the users to write up a brief description of the sections they used to solve a problem. For example what do all those abbreviations mean (TPS, ECM etc)

Understanding Abbreviations

Section OA

General Information
​

This section has information on how to jack your car, how to read production codes, what the abbreviations mean Torque values for fasteners etc.

​

Section OB
​

This section contains service information for the car. It also contains information on what OEM original fluids to use and basically covers what you need to know to maintain your car.

Or suppose you used the FSM to find the answer to a problem perhaps a short article on what the problem was and the sections you used to understand and solve the problem with the help of the FSM​

 

[vsg914]

I must agree about the value of a fsm. I know how to read them, and have one for all my Porsches'. I'm also a graduate of Southwest automotive school in OKC, and a factory trained chrysler mechanic (from the 70's and 80's). I now own a cabinet shop but keep a bay in the back with mech tools and a 2 post lift. The vette belongs to my wife, I just inherited it when we met (read: I get to work on it).

I purchased a fsm yesterday on ebay. Should be here by the end of the week.

Curt

 

[John Robinson]

I must agree about the value of a fsm. I know how to read them, and have one for all my Porsches'. I'm also a graduate of Southwest automotive school in OKC, and a factory trained chrysler mechanic (from the 70's and 80's). I now own a cabinet shop but keep a bay in the back with mech tools and a 2 post lift. The vette belongs to my wife, I just inherited it when we met (read: I get to work on it).

I purchased a fsm yesterday on ebay. Should be here by the end of the week.

Curt

I was mainly addressing all those who post that do not have a background as mechanics. It is good to know though what your back ground is it will help to add credibility to your future answers. As for me I was weaned on motorcycle racing as a youth and then was involved in SCCA racing and 30 years working for the general. My last 10 years were as a project manager in the prototype manual transmission build and validation for production. I now have a wood working shop in my garage were I build furniture. Which reminds me I have to get back to work.

 

[boomdriver]

I was mainly addressing all those who post that do not have a background as mechanics. It is good to know though what your back ground is it will help to add credibility to your future answers. As for me I was weaned on motorcycle racing as a youth and then was involved in SCCA racing and 30 years working for the general. My last 10 years were as a project manager in the prototype manual transmission build and validation for production. I now have a wood working shop in my garage were I build furniture. Which reminds me I have to get back to work.

Interesting background...similar to my own. Got introduced to grease thru moto-x racing and enduro. I actually came to own the worlds fastest production motorcycle in 1973 at the ripe old age of 16....(what was everybody thinking?) and spent most of the next decade involved in some form of racing or engine building for bikes. Found a career in heavy equipment engineering and stayed there until forced retirement just a couple yrs ago due to just being too damn wounded to do it anymore....
Now I sit on my patio and polish other peoples wheels, swing arms, brake levers etc....and do it at my leisure to add a small income to my pitiful retire/disability pension. This skill is a by-product of the 70's when I was porting aluminum heads for 4 cyl street/strip bikes. Back then nobody cared what the outside looked like....just the inside. Funny, as things evolved we learned that all of our effort was for naught, because polished intakes/runners/combustion chambers actually defeat fuel mixing in air and cause less power.......:eyerole
I'm amazed each week at the work that I can still produce when I enjoy what I'm doing.....and the exacting quality, something that might have been less when I was younger had it been the same job as I do today. Been exploring and learning about Corvettes ever since 1987 when I bought my first....I've had one ever since.

 

[vsg914]

Interesting background...similar to my own. Got introduced to grease thru moto-x racing and enduro. I actually came to own the worlds fastest production motorcycle in 1973 at the ripe old age of 16....(what was everybody thinking?) and spent most of the next decade involved in some form of racing or engine building for bikes. Found a career in heavy equipment engineering and stayed there until forced retirement just a couple yrs ago due to just being too damn wounded to do it anymore....
Now I sit on my patio and polish other peoples wheels, swing arms, brake levers etc....and do it at my leisure to add a small income to my pitiful retire/disability pension. This skill is a by-product of the 70's when I was porting aluminum heads for 4 cyl street/strip bikes. Back then nobody cared what the outside looked like....just the inside. Funny, as things evolved we learned that all of our effort was for naught, because polished intakes/runners/combustion chambers actually defeat fuel mixing in air and cause less power.......:eyerole
I'm amazed each week at the work that I can still produce when I enjoy what I'm doing.....and the exacting quality, something that might have been less when I was younger had it been the same job as I do today. Been exploring and learning about Corvettes ever since 1987 when I bought my first....I've had one ever since.

Wow. My professional mechanical career actually started in the USAF in 1966. Graduated Air Force tech school at the top of my class. First permanent duty station was at Laughlin AFB in Del Rio Tx. I promptly landed a part time job in Del Rio at a BSA/Yamaha dealer as a prep man and graduated to mech in a short time. I actually built my first bike from parts I found in the back room. 62 BSA 650. We had a 441 Victor that was stripped for the track. Went all over west Tx to AMA short track and TT's. Ended Air Force career in Southeast Asia as an F-105 crew chief. Got my a&e and a&p license after military service, but never worked on aircraft again. 42 years later, and I'm still wrenching, just not for a living