AC went out suddenly

[chefmike]

I was not sure if this was for the "electrical" section. I figured I would start here.

48 hours ago my ammeter was showing a larger drag than normal. AC was working fine.

Yesterday, no AC. The light on the AC button does not come on, nor will the fan switch to top vents. It will only do floor or defrost.

I checked all the fuses, they were fine.

Can some one point me to a good troubleshooting source or thread. I have yet to search. I am working ALOT of hours. I will try searching this afternoon or evening... but I figured I would post on the off hand chance it is one of those common boards or connectors you all can point out.

Thanks for all you guys have done helping me keep this girl running!

 

[WarWagon]

Remove the glove box and check for a two wire connector that melts down. If you find it melted replace the blower motor as it is drawing too much current. The fan switch on the HVAC control head is also known to go bad and that switch controls the AC compressor, usually it brings the compressor on with the fan off for a failure. Your case may require the entire control head being replaced with the vent mode issue. 1995 is common for the control head to go T.U.
Save you a search:
http://www.thetruckstop.us/forum/showthread.php?28385

 

[chefmike]

Ok, so the AC was back on when I got in the truck 2 minutes after posting this. Light came on and it works fine. Still no upper vents. So I guess I have 2 issues.

What am I searching here... is it a damper in the air system? I know the damper that closes off outside air does not work.


on to searching.... at least my feet have AC!

 

[chefmike]

Your case may require the entire control head being replaced with the vent mode issue. 1995 is common for the control head to go T.U.
Save you a search:
http://www.thetruckstop.us/forum/showthread.php?28385

Ironic that you answered right when I finally had time to check! thanks warwagon. I will read through that thread. At least now I have some terms for what I am searching. Guess this is going to be one of those fun tear-the-whole-dash-out projects...

On to read for 3 minutes before I start back to dinner service...

 

[chefmike]

So I read the pdf. First thing was check for blockages. I got down with a flashlight as I got home a few minutes ago (early night too!). I wasnt sure were the intake was, but looks like it is behind the blower motor, a flap was just inside of there, so I pushed it up. Boom, got top vents. At least I can enjoy good circulation while I troubleshoot. I should have time to pull her into my shop on Monday and check out the rest.

Great resource though war wagon. If that is not in the technical info, it should be!

 

[Mudbath]

Similar symptoms for me and it was the dash control unit, very easy to change and was an upgraded unit.

 

[chefmike]

Yeah... I realized I lost top vents again after bumping it to Max AC, so it must be the dash control unit. I have to look at the PDF warwagon linked again. I am not sure if that cheap fix is for a new unit to keep it from happening again or to fix a faulty old one.

Regardless I am now "fixing" my air intake to only take air in from the interior: here in GA MAX ac is wonderful, and I have not had that. My feet were FREEZING on the way to work today!

 

[WarWagon]

The fan switch is all you can replace on the 1995 for cheap. Otherwise replace the entire control head. I broke several tangs on my heat baked control head swapping the fan switch. Like $25 for the switch vs. $200+ for the control head. However the mode issues you have I would go ahead and just replace the control head. They are known to fail often on 1995.

Did you find the connector behind the glove box? This burned up will give you all sorts of trouble...

 

[chefmike]

I think I know which one it is, and I think I am ok. I put an alternate ground on my blower motor when I had to put a new one in last year.

Now to find a control head I guess!

Thanks for giving me the idea to just close that outside air door. I just never thought about doing that!

 

[chefmike]

Okay, so looking in rockauto, several choices:

1995 CHEVROLET C2500 SUBURBAN 6.5L 395cid V8 DIESEL MFI Turbo (F) OHV : Heat & Air Conditioning : Heater & AC Control Wiki Price
DORMAN Part # 76899 {#16135921} Temperature Control Knob Assortment
Temperature Control

- Stocked in outlying warehouse--shipping delayed up to 1 business day


$9.24
Add to Cart
ACDELCO Part # 1572055 {#16154598}
SWITCH,HTR & A/C CONT SEL AUX

$11.12
Add to Cart
ACDELCO Part # 1572275 {#16192099}
SWITCH,HTR CONT BLO
SWITCH,HTR & A/C CONT BLO w/A/C MAN CONT(C60)

$16.44
Add to Cart
ACDELCO Part # 1573379 {#12088531}
MODULE,AUX HTR & A/C CONT

Add to Cart
ACDELCO Part # 1572266 {#16233142}
CONTROL,HTR & A/C(W/R/WDO DEFG SW) w/ELEC RR WDO DEFG(C49) or A/C MAN CONT(C60)

$160.99

The first is the part behind the selector knob, the second is a black connector, the third is a green circuit board, and the last is the whole control unit (if I understand).

I am assuming the first one is cheap knob replacement. Anyone know what the second 2 are for?

It sounds like replacing the last one is the guarenteed fix.

 

[WarWagon]

2nd one is the blower speed and AC on off with blower switch. That is the cheap fix as outlined in the other article. I don't want to know what #3 is or where it is...

Check your rear window defrost options to match the proper controls.

 

[bosshog]

I'm having a similar issue with my 95 k 2500.I only have single air. Replaced the evap core and ac was working. I had very weak flow from the front dash vents. Next day, no recirc light , no ac light and no cold air at all. Itook it back to my mechanic. After reading this it sounds like I am having some similar issues.

 

[chefmike]

Just to document, I went with a cheap "fix" for now.

I pulled the wire harness on the vent activator motor, next to the gas pedal below the dash. Now the air stays at the top vents.

This will work for now. I was going to buy the control head, but my hydro boost pump started leaking, so that is where the $200 is going.

 

[davo727]

I got a new type ac delco 1995 controller from amazon for a lot better deal than rockauto

 

[chefmike]

No doubt... $105 shipped. Great call. Never thought to look there. Now I will...

Great heads up for anyone with the same issue.