95-99 HVAC "Control Head" AC light flickers w/ blower off & erratic or no airflow

[WarWagon]

Thanks to Ignacio (Nacho) Corella for pointing this out.
However it needs a better explanation of what is going on.

1995 Control heads are trouble prone and fail in ways beyond this repair. Newer control heads are also troublesome but not as often.

1995-99 will fail by running the AC when the blower is in the off position. It will also flicker the AC and recirculation button light. Sometimes the AC compressor will not turn on. Replacing the control head will fix the problem. However this article points out that the blower switch is the cause of the malfunction and is available separately for $20.00 vs. the $111.00 control head complete cost. Part number: 15-72275

The article is incorrect for 1995 as both buttons do not always light up and it does not require rec to be pushed in for the AC compressor to run with the blower off, just the AC button on with the blower off will run the compressor. Further the AC compressor can run with the light off. Been there seen that. Also the AC compressor will not turn on with the light on due to a control head issue - Not sure if it is this blower switch however.

I will be testing this blower switch for for INOP recirculation door light on 1995 very soon.

Other failures in 1995 require the replacement of the control head: heat from the vent when cold is selected. Random mode change from hot to cold that starts as an intermittent issue. Door mode being at the floor when dash vents selected etc also require replacement of the control head as the fix does not work for 1995.

For all years there is a wiring connector behind the dash that has the positive and ground for the HVAC unit. This connector tends to melt down. The ONLY way to properly fix it is to solder the wires and replace the shorted blower motor. A crimp connector WILL burn up in a short time. The Blower motor is drawing too much current and burning the connector up. I have seen this connector burnt on 1993 models and very common on 1995. Adding a separate ground wire from the blower motor to a good ground also helps.

For those that get really deep into the unit you can replace faulty transistors on the board of the control heads (Alternative repair to the one attached):

http://www.gm-trucks.com/forums/index.php?showtopic=83934

Article I describe above here:

http://www.aircondition.com/tech/qu...-through-1999-Chevy-GMC-Trucks-and-CK-Pickups
View attachment CK_Control_heads.pdf

 

[WarWagon]

Interesting, The blower switch fixed the AC light on issue. The plastic was very fragile and several clips broke - you may decide to go new after breaking the plastic so much.

The Rec light not going on was a burned out bulb. My Rec door is also jammed in the Rec mode - not a bad thing out here...

 

[WarWagon]

For all years there is a wiring connector behind the dash that has the positive and ground for the HVAC unit. It melts down. Add a ground to the blower motor. IMO the blower motor needs to be replaced due high amp draw when this happens. Others suggest the wire size is just too small. Crimp connectors will turn brown and melt after the repair so use a better fix like soldering the wires together then crimping them.
Melted wire pics courtesy of SnowDrift.

 

[WarWagon]

DO NOT USE THE A1 CARDONE replacement parts!!! The reman control heads from A1 CARDONE appear to be exchanges with no repairs done to them. A local shop went through like 7 control heads for a Malibu fleet as bumps can kick the AC button off. A Dealer part dropped in fixed the issue.

 

[THEFERMANATOR]

DO NOT USE THE A1 CARDONE replacement parts!!! The reman control heads from A1 CARDONE appear to be exchanges with no repairs done to them. A local shop went through like 7 control heads for a Malibu fleet as bumps can kick the AC button off. A Dealer part dropped in fixed the issue.

Last time mine went out, it took 3 before gm got me a working one.

 

[Cardone]

DO NOT USE THE A1 CARDONE replacement parts!!! The reman control heads from A1 CARDONE appear to be exchanges with no repairs done to them. A local shop went through like 7 control heads for a Malibu fleet as bumps can kick the AC button off. A Dealer part dropped in fixed the issue.

Hi guys, We don't reman "Control Heads". Where did you buy these parts?
We'd like to know if someone is selling parts under our name.

What was the stated part number? Any info you have would be great.
Thanks,

 

[RI Chevy Silveradoman]

Welcome to the Forum! :welcome2:

 

[WarWagon]

Hi guys, We don't reman "Control Heads". Where did you buy these parts?
We'd like to know if someone is selling parts under our name.

What was the stated part number? Any info you have would be great.
Thanks,

First off, Welcome.

Did your company ever reman HVAC "Control Heads"? Maybe they got some old stock.

 

[Cardone]

Hi guys,
Its not a product we've done in the past.

 

[WarWagon]

Hi guys, We don't reman "Control Heads". Where did you buy these parts?
We'd like to know if someone is selling parts under our name.

What was the stated part number? Any info you have would be great.
Thanks,

I have passed your info on to see if they want to look into counterfeit parts etc.

Understandably it is easy to confuse the lack of quality of YOUR parts with knock off parts because it wouldn't take much for a well painted knock off to actually be better than what you do sell.

Thankfully my favorite parts store doesn't carry your brand anymore. Part of the reason is below. The rest of us demand better and are willing to pay for it.

http://www.thetruckstop.us/forum/sh...e-can-the-booster-and-steering-box-be-flushed
http://www.thetruckstop.us/forum/sh...u-are-better-off-in-a-junkyard-for-parts-NSFW

 

[JMJNet]

Here is what I found out.

There are 2 types of AC Controller.
1. Older version where all the connectors are mounted on a plastic base and the PCB is large and it has some sort of transformer attach to it on the backside (shown in attached pictures).
2. Newer version where all the connectors are hanging on to loose cable and the PCB is smaller (as shown in the original post link from aircondition.com).

Both are found on a 95 model year.
Mine have version 2 and my Dad's (broken) have version 1.
He bought a new one from Amazon which appears to be version 2 (shown in link above from aircondition.com).

I tried to fix version 1 by changing all the transistors according to the link from WarWagon and some GM Truck forums but it does NOT fix it.

I changed one of the transistor mentioned in the above link for version 2 and it is now working nicely in my burb.
My symptom was when you rotate the blower button, it does not change the flapper door direction instantly, in a lot of cases, it takes more than 5 minutes of driving.
After I changed 1 transistors (cost around $1), when I rotate the blower selector button, it will change instantaneously.
The fix are specified in GMTrucks forum and you can also use google to find the appropriate replacement transistor.

Moral of the story, if you have version 1, better buy a new one (version 2).
Version 2, you can fix it by changing 1 transistor to fix the problem with blower selector button.

Yes, you can replace using version 2 although you have version 1 originally in there without issue.