Write-Up: HVAC Assembly

Yeah, I saw that too. :

VegasScott

Terminal Dropped... Everything back to normal.

VegasScott

amazing....

what does Terminal Dropped mean?

deekster_caddy wrote:

what does Terminal Dropped mean?

I'm thinking battery terminal. let's see if I'm right

LARRY70GS wrote:

I'm thinking battery terminal. let's see if I'm right

Ding! Ding! Ding! WE HAVE A WINNER!

My posts from my phone are always a pain in the butt, so I type as little as possible when using it.

VegasScott

99Rivman wrote:

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 having the problem where only hot air is blowing out of the drivers side, middle vents & rear vents but I cant seem to get the #3 actuator out? Do I have to remove my cencer console? Any advice or assistance world be greatly appreciated.

Add a can of freon. Trust me, it will take care of your problem!!!!!!!!!!!!!!!!!!!!!!!

https://rivperformance.editboard.com/t1867p135-faq-warm-hot-air-on-drivers-side-cold-on-passenger-side

96RIVMANN wrote:

Add a can of freon. Trust me, it will take care of your problem!!!!!!!!!!!!!!!!!!!!!!!

https://rivperformance.editboard.com/t1867p135-faq-warm-hot-air-on-drivers-side-cold-on-passenger-side

this may be the case (very likely from what I've seen here), but whatever you do please do NOT blindly just add a can of freon. You must at minimum check low pressure, and if you really want to know what is happening high pressure too, before and after you add freon. Do lots of people add freon without checking? Yes. But there are more things going on than just low pressure in your A/C system, and making sure both high and low pressures are within spec is an important step. If the low side is below spec and adding a can fixes all your problems you are lucky. Have someone put gauges on both sides after you are finished just to make sure everything is okay. I bought a cheap (but nice) set of gauges at Advance Auto Parts for $80.

96RIVMANN wrote:

Add a can of freon. Trust me, it will take care of your problem!!!!!!!!!!!!!!!!!!!!!!!

https://rivperformance.editboard.com/t1867p135-faq-warm-hot-air-on-drivers-side-cold-on-passenger-side

Thanks for the reply.. I did add some refrigerant but I am at the highest pressure via the gauge on the can. What pressure is our car supposed to be at? I can hear the compressor kick on but it didn't fix my issue.

deekster_caddy wrote:

96RIVMANN wrote:

Add a can of freon. Trust me, it will take care of your problem!!!!!!!!!!!!!!!!!!!!!!!

https://rivperformance.editboard.com/t1867p135-faq-warm-hot-air-on-drivers-side-cold-on-passenger-side

this may be the case (very likely from what I've seen here), but whatever you do please do NOT blindly just add a can of freon. You must at minimum check low pressure, and if you really want to know what is happening high pressure too, before and after you add freon. Do lots of people add freon without checking? Yes. But there are more things going on than just low pressure in your A/C system, and making sure both high and low pressures are within spec is an important step. If the low side is below spec and adding a can fixes all your problems you are lucky. Have someone put gauges on both sides after you are finished just to make sure everything is okay. I bought a cheap (but nice) set of gauges at Advance Auto Parts for $80.

You do need to check the pressures, putting in too much can cause problems too.
Another way to check the system is to set it at the lowest temp setting and listen/watch the compressor. What this does is override the temp readings and tell the system to run at max, if the compressor cycles that also tells you the Freon is low.

Anyone have a write up for glovebox removal to reach this HVAC component?

charlieRobinson wrote:

Anyone have a write up for glovebox removal to reach this HVAC component?

Glove-box comes out pretty easy, set of screws under the hinge. I know this sounds, well, terse but all you do is empty the box then unscrew the box at the hinge. If you look you'll see them. Take your time, no worries.

sorry, didnt mean removing the glovebox. I meant, how do you get the HVAC out of the glovebox area? Seems like you have to take more than the door of the box off to get back in that left corner.

I was looking at gmpartsdirect.com and was looking at the parts diagram for the hvac and it lists a filter for the hvac system. Part number 6 is the filter and part 7 is the filter retainer. http://www.trademotion.com/parts/1998/BUICK/RIVIERA/?siteid=214858&vehicleid=1303322&diagram=AD95066 I always heard that we didn't have an HVAC filter on our system. Is that a different filter than what I am thinking of?

I think whoever said that meant there is no SERVICEABLE filter, or cabin air filter. That looks like some kind of permanent filter, not sure of its purpose.

This thing is my problem. I've tried every which way to remove it short of taking the dash apart. How does it come loose? I need to get to the actuator directly above it but can't work with it in the way.

I feel like an idiot for asking, but what am I doing wrong? LOL

I am tackling #2 actuator on the drivers side. Is it possible to take it off from underneath? only taking the 3 screw plastic plate to get to it? Or must more of the dash come off?

If #2 doesn't look suspicious I will check #3. I am getting hot air on drivers side, middle, and rear.

Got the 2 button plug breakpedal harness things off. A quick 180 turn and pull. looks like I have almost enough room to get to the actuator now. Im with Tajis at this point. It would be a lot easier to work if I could get that duct elbow out of the way. Any protips from someone with experience on this part of the car?

I think those 2 buttons that are mounted to the brake pedal are for ABS and traction, maybe?

I've 'somewhat' managed to get to the bolts that mount the actuators on. I had to use a very small quarter inch ratchet and still haven't managed to get to all the bolts.

I may have made more progress. Apparently a tool called a "Thumbwheel ratchet" or a "Finger ratchet" will make this job a whole lot easier. It's basically a round ratchet head without a handle that fits in over the screw and gives a thumb grip to twist the screw by hand.

Tajis wrote:

I may have made more progress. Apparently a tool called a "Thumbwheel ratchet" or a "Finger ratchet" will make this job a whole lot easier. It's basically a round ratchet head without a handle that fits in over the screw and gives a thumb grip to twist the screw by hand.

Tajis, any luck so far?

The thumb wheel ratchet does make a big difference in removing the screws. I was able to get the middle actuator free without incident, but I'm having trouble with the one closest to the driver. "Number 3"

I can 100% confirm that the original diagram is backward. The middle actuator controls the heat/cold mix on the driver's side. Number 3 will be the one that controls the vents. Using the thumbwheel ratchet I was able to remove number 2 from the bottom, so it is possible.

For number 3, I believe you'll need a screwdriver with extension and quarter inch bit to reach the recessed socket. Still in the process of trying to figure that one out.

Success! I now have air coming through my middle vents!

For the number 2 motor, get a thumbwheel ratchet and feel for the bolts. Attach the ratchet and twist the bolts off. Keep in mind you're basically doing this blind due to the vent being in the way. This is the motor that mixes hot and cold for the driver's side.

Number 3... That's the one that is a PITA to remove. The bolt furthest away from the driver's seat on the number 3 motor is easy to remove. The thumbwheel ratchet will fit right on and have it off in no time. The one closest to the driver's seat is hard to remove. Remove the hard to reach bolt first, since if you don't the whole actuator will be wobbling and trying to get in the way.

I ended up getting a six inch long, quarter inch wobble socket extension. You cannot do this without a wobble socket. This let me flex the 7/32 connector down onto the bolt (with several tries). You will have to run the extension through the open middle of the nearby support arm thing. The socket will not get an easy grip, but it WILL come loose with enough persistence. I ended up holding part of the extension down so that the socket remained angled correctly.

Also, if you have a helper it helps if they hold a flashlight toward the main set of vents over the shift stick. It's the easiest way to get a light on where you're aiming.

Once this is off you'll be able to either replace the part or otherwise manually route the air back up to the vents!

I hope this helps someone not have to go through the trial and error process like I did.

charlieRobinson wrote:

Got the 2 button plug breakpedal harness things off. A quick 180 turn and pull. looks like I have almost enough room to get to the actuator now. Im with Tajis at this point. It would be a lot easier to work if I could get that duct elbow out of the way. Any protips from someone with experience on this part of the car?

I think those 2 buttons that are mounted to the brake pedal are for ABS and traction, maybe?

buttons on the brake pedal - top one (usually blue) is cruise control, bottom one is brake lights and a signal line to the electronic brake control or some such - it's in the factory manual.

By the way you might want to remove those buttons (the holders are keyed, remove the plugs then twist them and remove0 and open up the switches and check the contacts. I checked mine this week for PM and found the contacts were burned--burned bad in the brake lite switch, not so bad in the cruise switch. The cruise switch cleaned up with a little sanding. I replaced the brake light switch. Again they are not very expensive, you can find them for under $10 each if you look hard enough.