Write-Up: HVAC Assembly

Thought I’d put this out there just in case anyone else is having problems with their HVAC.
The first picture is of the driver’s side of the HVAC Module Assembly and the actuators that attach to that side, there are two more on the passenger side. The three on the driver’s side are the same part number and the two on the passenger side are the same also but they will not interchange from left to right. If you have problems with the air mix to either the A/C or Defrost or Heater these actuators are more than likely your problem.
The actuator has a 5 volt motor in it that turns gears that open and close the air mix doors. I had one that had gotten stuck on my first Silver Arrow and was able to free it up and it has been fine ever since. I was having problems on the new Silver Arrow, air wouldn’t go to the heater vents, and that was what I was looking into. After removing the left sound insulator I found out why! Some idiot had removed the #3 actuator in the picture and the air vent! Luckily they are the same for all years of the Riv so I was able to replace both parts with parts from my spare ’95.


The actuators are listed as follows:
1 Defrost Actuator
2 Mode Actuator
3 Air Mix Actuator


This is the vent part that someone had removed!

Hope someone finds this helpful.

I've been having temperature blend problems on my passenger side, but otherwise everything is working fine. When the pass side vents are on the air coming out is either full heat or full cold, no in between. I haven't torn the dash apart yet to go digging... How much of the dash did you have to take apart to get at those parts you show?

Thanks
-Derek

deekster_caddy wrote:

I've been having temperature blend problems on my passenger side, but otherwise everything is working fine. When the pass side vents are on the air coming out is either full heat or full cold, no in between. I haven't torn the dash apart yet to go digging... How much of the dash did you have to take apart to get at those parts you show?

Thanks
-Derek

These on the left side are accessible by just removing the sound insulator from under the dash. Three screws, the light socket, and the OBD II connector and its out. They are somewhat hard to reach, especially since I'm too old to be working in that position, but they are accessible.
The problem you are having on the passenger side is almost the same problem I was having on mine. It was blowing hot air out the passenger vents even with the A/C on full cold.
To get to the passenger side actuator you remove the glove compartment and it is right there on the side of the HVAC Module. Mine just seemed to be stuck in one position, I opened it up and put voltage directly to the motor and got it moving and it has worked ever since. I used a battery holder from Radio Shack, three AAA batteries that made 4.5 volts and it did the trick for me.

sweet, thanks. I'll give that a try, this summer when it warms up

My temp control and air direction functions work, but the blower only works intermittently. I'll turn it on and it won't blow then it'll blow for a second then off, then about a minute, then off. I'm thinking about replacing the blower motor but I'd like to know about accessing it. You guys think I'm on the right track? Keep in mind, Ohio freezes early and stays frozen long.

dear captshiner

maybe it's the motor, maybe not. Also check the power. I do not remember whether the HVAC fan is on a fuse or circuit breaker. And my riv's in the shop this week (repair small rust spots under trunk lid and around tail lights, repair trunk water leaks, repaint bumpers, repaint pinstripes, and repair Parking Lot Pox in the passenger side rear fender) so I can't run out and check.

If your HVAC fan is on a breaker, you may want to simply replace it. Your problem sounds like some contact point in the power to the fan is heating up then letting go, which could be teh breaker, a connection in the fan motor, or some other gremlin.

It also could be an issue with the HVAC controller. That controller sets the fan on and off and checks the speed. If I recall right, some of that functionality can be checked with the dealer's Tech II or computer scanner (I forget what the new PC-based scan tool is called). For instance, the Tech II can "command" the fan on and off to see if it behaves. If so, problem is most likely the controller. If not, problem is fan or wiring between it and the controller.

Albertj

How much do you think it would cost me to have the scan done at the dealer? I bought it from a friend of the family who happens to be an electrical engineer so he should probably be able to troubleshoot wiring problems better than I can. I'll call him and see what he's up to after I get the new halfshaft put in tomorrow.

I have heard of this problem being caused by a bad relay/speed controller. I forget exactly what we call it in these cars.

deekster_caddy wrote:

I have heard of this problem being caused by a bad relay/speed controller. I forget exactly what we call it in these cars.

I'll look to AA for this answer, he's always got it.

albertj wrote:

dear captshiner

And my riv's in the shop this week (repair small rust spots under trunk lid and around tail lights, repair trunk water leaks, repaint bumpers, repaint pinstripes, and repair Parking Lot Pox in the passenger side rear fender

Albertj

Albert, may i ask how much you are paying for all this to be done, so I have a rough idea how much I will be paying next spring to have the same work done. Thanks,

Anthony: The body repairs will come in under $1,000. The money-for-nothing part is the pinstripes, $100/side. The bargain is the trunk repair. The goofy one is the passenger side rear fender, only a body shop guy could see those dents, you can't see them unless the light hits them just so. I guess the thing is, the DRIVER side is Pristine.

We agreed on $750 not including the pinstripes but I am expecting to owe a bit more once Tom gets into it. He's not the cheapest body shop in town but he's more reasonable than the dealer and he's a semi-gearhead (you should see his '57 Tbird and '63 Impala convertible). If he has a weakness it might be burning a little rubber on test drives with customer's high-spec cars (I did NOT say that...)

Then after that I am getting the exhaust done, replacing mufflers with Hooker Maxflows. Only problem I am having now is deciding whether to replace the resonator and with what. I want the exhaust to be silent unless I punch the loud pedal... that Buick Burble at idle would be nice to keep though.

Albertj

Captshiner - my dealer charges me 1/2 hour labor just to do a scan ("check and advise") they call it.  

Just remember that what the scan says does not necessarily point to some part to replace.  Just because the scanner says something's not sending a signal does not mean that sensor or whatever is busted.  It could be the wiring to it or some such.

If I am not mistaken there have been service bulletins out for the HVAC controller - that does not mean a recall but it means there's a problem that crops up a lot.  I do not have any TSBs,  maybe someone who can get to them can comment.  If you get a control unit from Ed Morad it'll work.  If you go to a pick and pull that has some Rivs even better, they are not hard at all to pull once you get the dash panels off.   Do a Search on this site to find that write up, it takes a little time but is not difficult.  

Albertj

I have access to the SB's for the Riviera.
I looked in HVAC section headings for HVAC Controller and could not find. If you can give me specific SB #, I'll be be glad to copy and forward to whoever needs it.
Rick

MY A/C, AND HEAD A/C HEAD UNIT HAS STOPPED WORKING ALL TOGETHER WHEN EVER I GOT A TV PROFESSIONALLY INSTALLED, I BROUGHT IT BACK THEY SAID IT WAS LIKE THAT BS!!! ANYWAYS I WORK AT A SHOP AND THE TECH 2 BROUGHT UP A DTC34 LOSS OF DATA TO HVAC PROGRAMMER, CAN ANYONE GIVE ME SOME MORE INPUT OR ADVICE ON HOW TO GET ICEY AGAIN IN THIS HEAT, LATA

This is what the ’95 Service Manual has for that code, if it is a different year the information could be different? I have a ’99 manual also if you would want to try that one?



HTH

superivicharg wrote:

MY A/C, AND HEAD A/C HEAD UNIT HAS STOPPED WORKING ALL TOGETHER WHEN EVER I GOT A TV PROFESSIONALLY INSTALLED, I BROUGHT IT BACK THEY SAID IT WAS LIKE THAT BS!!! ANYWAYS I WORK AT A SHOP AND THE TECH 2 BROUGHT UP A DTC34 LOSS OF DATA TO HVAC PROGRAMMER, CAN ANYONE GIVE ME SOME MORE INPUT OR ADVICE ON HOW TO GET ICEY AGAIN IN THIS HEAT, LATA

please add the year of your car to your signature.

superivicharg wrote:

MY A/C, AND HEAD A/C HEAD UNIT HAS STOPPED WORKING ALL TOGETHER WHEN EVER I GOT A TV PROFESSIONALLY INSTALLED, I BROUGHT IT BACK THEY SAID IT WAS LIKE THAT BS!!! ANYWAYS I WORK AT A SHOP AND THE TECH 2 BROUGHT UP A DTC34 LOSS OF DATA TO HVAC PROGRAMMER, CAN ANYONE GIVE ME SOME MORE INPUT OR ADVICE ON HOW TO GET ICEY AGAIN IN THIS HEAT, LATA

OK so you work at a shop... did you pull the dash yet to see if maybe the wires to the HVAC head are not completely seated? Since you work at a shop, taking the dash off yourself and having a look back there should not be a big deal. Please do it and tell us what you find.


Albertj

thanx dude im gonna hit that up so i can get to the bottom of this

yea i bought a new a/c head unit when i bought the car cuz the bulbs on the fan button didnt light up, it worked til i got a tv installed, i have a wiring diagram for the hvac and a green&black wire runs through the radio harness and the hvac harness, im not the best with tracing down wires but the code pulls up the same thing everytime, its just the hvac programmer is $500 and i want to know for sure thats it, i would take it to the dealer but they gonna tell me what i already know besides replacing the programmer

are you saying that the TV got wired into the HVAC harness?

probably the thing to do is

1) hope they did not fry the AC controller
2) there are empty positions in the fuse panel, a GM dealer should have the bits you need to add a fuse and then you can run a wire to the TV instead of taking power from the HVAC circuit.  If the power drain from other stuff on that circuit (a TV, natch) is too high a low voltage condition might result.  Some solid state electronics don't like to run right with voltage too low and may malfunction or be destroyed as a result.

You will need the wiring diagram in the installation manual for the TV to figure this one out; it's been pointed out before on this forum that Rivs really do not like electrical aftermarket accessories...

good luck...

Albertj

HAS ANYONE REPLACED A HVAC PROGRAMMER BEFORE I JUST BOUGHT A NEW FROM THE DEALER FOR $500 AND INSTALLED IT AND NOTHING HAPPEND IT DOES THE SAME THING AS BEFORE NOT A THING, THE DEALER SAID TURN THE KEY SWITCH ON FOR 3 SECS AND BINGO, WELL I NEED HELP FROM A RIV OWNER

Yes I have, and I bought it from the salvage yard for $10. All the lights worked and after I plugged it in everything was fine. I don't see why anyone would wire a TV through the HVAC controller? I'd take it back to the person who installed the TV and tell them to rewire it.

superivicharg wrote:

HAS ANYONE REPLACED A HVAC PROGRAMMER BEFORE I JUST BOUGHT A NEW FROM THE DEALER FOR $500 AND INSTALLED IT AND NOTHING HAPPEND IT DOES THE SAME THING AS BEFORE NOT A THING, THE DEALER SAID TURN THE KEY SWITCH ON FOR 3 SECS AND BINGO, WELL I NEED HELP FROM A RIV OWNER

HOLY CAPS LOCK BAT MAN

I replaced my HVAC head unit and it just plugged in and worked. Have you checked all your fuses? Do any lights come on?

albertj wrote:

are you saying that the TV got wired into the HVAC harness?

probably the thing to do is

1) hope they did not fry the AC controller
2) there are empty positions in teh fuse panel, a GM dealer should have the bits you need to add a fuse and then you can run a wire to the TV instead of taking power from the HVAC circuit. If the power drain from other stuff on that circuit (a TV, natch) is too high a low voltage condition might result. Some solid state electronics don't like to run right with voltage too low and may malfunction or be destroyed as a result.

You will need the wiring diagram in the installation manual for the TV to figure this one out; it's been pointed out before on this forum that Rivs really do not like electrical aftermarket accessories...

good luck...

Albertj

Referring to the above: are you going to continue posting in caps or are you going to roll up your sleeves and get the installation manual for the TV and figure this out?

If you are not able to do that (that's OK not everyone wants to dive into car wiring, it's not their cup of tea) the thing to do is go back to the installation place and tell them please take the TV out and restore the wiring to factory spec.

Albertj