2nd opinion on Climate Control Module

[bozr]

I just bought a 99 Buick Century Limited, excellent car so far. The problem is climate control does not work. The previous owner said his mechanic told him it was the Climate Control Module. Is there a way to test this?
The mode buttons light up when pressed but the digital display is blank. The compressor cycles but the blower never comes on in any mode. Temperature setting display works.

I'm new to Buicks so any help would be appreciated.

[Herb1949]

My problem is similar. 1999 century, the drivers side of the dual climate control never gets cold. Appears that the heat portion never completely turns off. The passenger side works great. Have checked auto parts stores for a manual to assist in t-shooting, no luck.
all assistance appreciated.

[richtazz]

bozr, many of the test proceedures for diagnosing HVAC issues are beyond the DIY'er. It involves a lot of technical data and circuit testing, as well as some specialized equipment. The blank display may only be a burnt out backlight bulb. Try shining a flashlight at the display and see if you can read it then. If so, there is a self diagnostic mode that will display the HVAC trouble codes on the control display.

Herb1949, the first thing I would check is your refrigerant charge with a set of guages. The way the system is designed, a low charge will cause warm air on the drivers side while still providing cool air on the passenger side. If the refrigerant pressures (high and low sides) are fine, then I would suspect the drivers side temp door actuator is bad.

[Herb1949]

Well, I gave up and took it to an AC shop for diagnosis. He says the charge is fine but the control module is bad with a total price tag, parts and service, of $753 + change.

I forget what the price quote on the part is. I'm going to check into buying the part and installing it myself. If I have to pay that much for the AC to work, I'll have to do without.

[bozr]

Update;
There were actually two problems. First the blower motor was burned out. After that everything seemed to function ok except the display on the module.

I bought a used module for around $40 off Ebay. It was guaranteed to work but the display was out on it too. For anyone that wants to go the easy route with this there are a few people that fully rebuild it for around $80 on Ebay. The module can be removed from the dash in 5 minutes, 4 screws two clips and the connector.

For me the difference between $40 and $350+(the cost of a new module) can buy a lot of tools, so I did a little research. It seems the display going out is a common problem. The cause is bad solder joints on a series of surface mount resistors on the modules circuit board. I’ve successfully repaired the displays in both modules. I'll give details and pictures in another post, I’m out of time for today.


Edit

The rest of the story is here;
http://www.automotiveforums.com/vbul...d.php?t=921143

[Herb1949]

Originally Posted by bozr

Update;
There were actually two problems. First the blower motor was burned out. After that everything seemed to function ok except the display on the module.

I bought a used module for around $40 off Ebay. It was guaranteed to work but the display was out on it too. For anyone that wants to go the easy route with this there are a few people that fully rebuild it for around $80 on Ebay. The module can be removed from the dash in 5 minutes, 4 screws two clips and the connector.

For me the difference between $40 and $350+(the cost of a new module) can buy a lot of tools, so I did a little research. It seems the display going out is a common problem. The cause is bad solder joints on a series of surface mount resistors on the modules circuit board. I’ve successfully repaired the displays in both modules. I'll give details and pictures in another post, I’m out of time for today.

One shop told me that the computer will set failure codes and they need to be reset so that the system will work proplerly. Has anyone else heard this? Is it true or were they just trying to scam me?

[bozr]

Herb1949, I have to agree with richtazz.
That is a common symptom of a low refrigerant charge or another problem with the AC. I don’t see anything that points to a bad control assembly. I’d get a second opinion.

The HVAC Controller in the ‘99’s (98-05 Century) report faults to the computer as DTC’s but will not necessarily illuminate a check engine light. Check with your local auto parts store, they may have a scanner to link to your computer. If there are any trouble codes, write them down. If their scanner is capable you can clear them. Try this first to get closer to the problem.

[Herb1949]

I took it to 3 different shops. I finally decided that it must be the controller when a shop that does recharges said that it must be the controller and they don't have the expertice to fix it. They said that I would have to find a shop to do the work.

If a recharge would have fixed it they would have made more money off of me than they did. They had a check AC system special where the check was free. They would have made $59.95 plus cost of refridgerant if they had serviced it but as it is, they made nothing.

OBTW, I will take any car to them that needs a recharge.

I ordered a controller from an online website for $80. I'll post how it works and the website when I get it and have it installed.