Ok Folks here is a lengthy DIY for the removal of the HVAC system in a 2nd Gen Ram. Now this was done on a 1998 Ram 1500 Quad Cab. Some areas may vary and the number of bolts may change. I assume no responsibility to what you do to your truck. This is simply how I was able to remove my HVAC system. Yours may be different. So if you break it sorry that is on you.
Do not fear the Dash. It is not a really hard project. Just time consuming.
These instructions somewhat follow the repair manual. As a Warning you may very well crack your dash if it isn’t trashed already. As in all repairs disconnect the negative terminal. IF you think it will be ok to stay hooked up I think you are nuts. You will be messing with the Airbag system So be sure to undo the NEG terminal and let it set. Also before starting this project take your vehicle somewhere to release all the freon and pressure before starting.
Link to the Service manual!
http://www.ramforum.com/f77/2nd-gen-service-manual-986/
Step 1: Remove the hood latch from the under part of the dash.
Step 2: Remove the parking brake by removing the three nuts that secure it to the firewall. Slide it over out of the Way.
Step 3: Unplug the wiring under the dash for the ignition and gauges. There are 3 connectors.
One connector near the firewall that is a clip in connector.
Another one is beside that with a bolt in it. The bolt is 10mm loosen that and it will pull out.
The next one is a push type clip. Push down on the clip on the side and slide it out to remove it.
There are 2 on the passenger side. Under the glovebox.
Next remove the Side kick panels. The ones that are tucked up under the dash on the outside. The manual calls them a trim piece. Pull them off of the door seal and push them forward towards the firewall. Then pull outward. They will come out. No bolts or anything are holding them in.
Step4: Remove the cover for the airbag module in the center. This is the cover with 2 screws on the transmission hump. Then remove the module bracket. There are 2 bolts and 2 nuts to remove. Remove these and the bracket. There is no need to unplug the module.
Step 5: Remove the lower dash panel from under the steering wheel. There are 3 screws that hold it on at the bottom. After removing those 3 pull down on the panel and out. There are 2 pop clips behind there so be careful. While under the Steering wheel unplug the wiring harness for easier access.
Step 6: There are 2 bolts that hold the steering column to the dash. Remove these 2 bolts and lower the steering wheel.
Step 7: Go to the engine bay and unclip the shifter linkage. Go back inside and remove the 3 nuts that hold the steering column to the firewall.
Optional step: After you have the steering wheel down there is a brace plat at the base of the dash that held the under steering column cover. That can be removed for more space. It is 8 screws and the plate will drop allowing for more room to lower the column and remove the dash if you wish.
Step 8: Remove the A pillar covers. The passenger side is held on by clips and screws. Remove the handle inserts to access the screws. Remove the screws and then pull down on the top of the cover. These are held in place by more pop clips so be careful to not break them.
Step 9: Remove all the top screws in the upper dash by the windshield. Removing these will allow the dash to roll forward. To gain access behind the dash you may need to loosen these screws so that you can slide the dash back and lift up to remove it from these bolts.
Step 10: After the dash is rolled forward there are a ton of wires connected on the drivers side. Unless you are going to remove the dash I say leave them connected.
Step11: You will now see the exposed HVAC BOX. This is the ********* thing. It is held in on both the interior and the engine bay. This is where all the fun begins.
Step 12: Remove the AC coolant lines from the box in the engine bay. The lines that go from the box to the condenser. Also remove the Coolant lines that go to the heater core. They may be stuck on there so be prepared for a fight.
Step 13: Enter the engine bay again and be ready for some interesting yoga moves. There are several nuts that need to be removed to free the box from the firewall.
One is above the intake in the back of the firewall all by itself.
Another is on the PCM plate.
Another behind the PCM plate.
And a few in the PCM Plate.
They all look similar in the engine bay.
In the interior there is one tucked up under the lip where the dash was and one behind a ground. There may be one or 2 more or less on your model.
Step 14: After removing all the nuts the box should be able to be wiggled. Wiggle it around while pulling on it so it will move be careful to not yank too hard as there are vacuum lines behind it.
Step 15: The vacuum lines are still connected so pull it backward to where you can see behind it. Remove and label all the connections so the proper color goes back in the same spot. There is one Black line that runs to the engine bay you may have to remove that in the engine bay.
Step 16: After the box is almost free on the top there is a wire attached to a lever. You need to remove the wire from the actuator then remove the hire holder. I used a pair of pliers and just played with it till it came out. It pulls up.
Step 17: Remove the box from your vehicle.
Reverse these steps for reinstallation.
