Heater control unit removal

You will want to follow these instructions if you have a heat problem and have a pushbutton control unit. I have a manual unit and didn't realize until I had it all dis-assembled that I was on the wrong path. I eventually flushed the core and it works fine now. See my other post here on that operation.

If you do need to remove the control unit, take a deep breath, crack a beer and pray for patience because removing the trim and dash parts is a pain.

1. Start by removing the center radio console trim. You'll first remove two screws at the top which are above the heater control unit. Then remove the ash tray and then slip a flat bladed screw driver into the back of the hole where there is a white clip. Push the white clip up gently to release it, then grab the black trim at the top and bottom and give it a good pull. There are four detent clips that will pop free - two on either side at the bottom of the trim and two between the radio and the heater control. I've included some pictures of how these two trims fit together after I removed them so you can see how they fit together. When you remove the black trim, you will need to disconnect the cigarette lighter.

2. Once the black trim is removed, there are four gold colored 8mm bolts that hold the radio and utility container to the console outer trim. Remove the radio, disconnecting the antennae and radio connectors. 

3. Now remove four screws that hold the heater control to the outer console bezel. There are two on top and two on bottom of the unit.

4. Now you'll need to remove the lower dash panel on the passenger side to expose an upper screw to remove the remaining console bezel. Remove the glove box door and glove box, disconnecting the door sensor and light. To remove the lower dash panel, there are four 10mm bolts on the bottom edge, two grouped on the left and two on the right. Then there are two 10mm nuts to remove on either side of the glove box hold. Remove these and the panel should pull straight out.

5. You should be able to see the screw holding the upper and lower corner of the center console bezel. Remove these and then move to the driver's side. 

6. Remove the driver's side lower dash panel. As with the passenger side, there are four 10mm bolts attaching the bottom edge of the dash panel, group in two's on the left and right.

 

7. Now remove the two 10mm bolts on either side of the steering column, hidden behind two small panels. On the left side, there is a small panel that includes the dash light control. Pop the coin holder from the middle and you will see the recessed bolt, about 3" into the panel. Remove.

8. On the right side of the steering column, there is a small panel housing the cruise control. Pop the right side blank panel (blank on my car) and you will find the other recessed 10mm bolt. Remove and then pull the panel out about 6". You will need to disconnect the cruise control connector, the dash panel light control and then the hood release cable. The panel should come free at this point.

9. Now you should have access to the last screw on top and bottom of the right side of the center console bezel. The bezel should pull out, working around the heater control unit. There is also a detent at 12 o'clock on the bezel (shown in the picture below, right in the middle of the photo) that you will need to pull from behind. Give it a sharp tug and it should break free. The bezel looks as below in the second picture when out of the car.

Re-assemble in the reverse order. Hope this helps!

Heater core flush

The flush operation is pretty simple (compared to attempting to remove the heater control unit in the dash which was before I realized that the manual unit my car has doesn't have a pc board to check for cracked solder joints like the pushbutton models do. I'll do a separate post on how to disassemble the dash to remove the control unit for anyone that needs to do that).

So, the issue is there is no heat in the car. The fan works, and all the slider controls work as well. I check the heat selector in particular that actuates a valve on the firewall, allowing more or less radiator fluid through the heater core depending on the heat selection. The valve operated easily as I changed the heat selection.

I warmed the car up and checked both the inlet and outlet hoses (they are just above the valve in the picture, going through the firewall) and sure enough, the inlet hose (going from the valve to the firewall, far side) was good and hot but the outlet hose (pictured in the middle between the valve and the inlet hose) was lukewarm at best. I attempted to remove the hoses at the firewall and had two issues: the hose clamps are royal knuckle busters to move if you don't have hose clamp pliers. I did it with channel locks and a needle nose but it was not fun. The second issue was I could not break the hose loose from the inlet and outlet pipes. They are copper pipes and I was worried I would break them if I wrestled the hose any harder, so I removed the hoses at the other ends. Both hose ends are below radiator height so I had to plug the outlet pipe on the water manifold and inlet pipe on the block to keep from losing too much fluid.

The flushing was pretty simple. I placed a harden hose sprayer in the end of the inlet hose to start, and slowly increased pressure until I had good flow on the other end. Brown, muddy fluid came out which is a good indication it was blocked and not getting good flow. I switched back and forth between inlet and outlet hoses until the water ran clear in both directions. I reconnected the hoses, fired the engine back up and let it warm up...and booyah! Hot air is now blowing from the heater.