Originally Posted by AdamCrosier (Post 278959)

Figured I'd post my notes for any others attempting this one on this year.

EDIT: High resolution pictures on this album http://s149.photobucket.com/albums/s55/thenewvintagehome/2001%20Chevrolet%20Blazer%20LT%20heater%20core/ Make sure you click on them to get the description at the bottom. Click again to get the high resolution. Sorry! They're not in order, but are labeled by the number on this list. This isn't necessarily the best order, and you'll notice in the pictures that I realized going through it that I should do things differently. Hope this helps you all!1. Battery off - don't need airbags going off in your face!
2. Lift passenger door threshhold out, pull out kick panel3. Remove two 7mm bolts holding passenger lower panel4. Remove 4 7mm bolts for middle panel with 12v accessory receptacles
5. Disconnect harness from middle panel (not at the receptacles)6. Remove two 7mm bolts from the OBDII connector on lower drivers panel under dash.7. Remove 4 7mm bolts from lower drivers panel
8. Disconnect electrical harness from panel to remove (pinch blue connector)9. Disconnect parking brake release cable under dash from the lever (push cable grommet out of the holder and diconnect end of cable.10. Remove single 7mm holding courtesy light to drivers panel
11. Remove 4 7mm bolts and remove panel - feed parking brake cable through the hole in the dash12. Remove three 7mm bolts at instrument cluster (one in middle on top and two underneath)
13. Start to pull out the dash trim bezel, enough to push the back wiper/back hatch button out of the bezel, allowing you to disconnect the harness.14. Open glove box completely by pushing up the spring that keeps it from falling open.15. Remove air bag harness (yellow wires) next to main harness, and remove main harness by unscrewing middle bolt. There are two blue clips that I pulled out, but can figure out if I needed to or not. Remove at your discretion.16. At left side, remove harness from headlight switch and remove bezel.17. Remove radio (2 7mm bolts if stock). Two harnesses and antenna to remove. Now, if you have the cassette, you can either remove the center console or feed the cassette umbilical through the dash. I ended up doing both. To remove console, pull out cup holder rubber and remove two 10mm bolts. Open storage pocket at arm rest, pull out center, and remove two 10mm bolts. Center console is free. Either disconnect cassette wiring or if you have help, when the dash is free, take it with you. I fed the wires from the radio area down out of the dash, but later removed the center console anyway. If you feed the wires, you do not need to remove the center console.18. Remove speaker grills under windshield - 2 7mm bolts. On the passenger, if so equipped, twist the light sensor (a quarter turn I think) to remove and leave the sensor in the dash.
19. Remove defroster grill. Careful - delicate. There are clips on the top (by windshield) and bottom (toward interior of car), four pairs. Remove light sensor as above.
20. Remove 6 upper bolts: one in each speaker bay and four in the defroster duct.
21. Remove 8 bolts and L brackets on either side of the steering column.22. Remove 1 10mm bolt behind where brake release was, and one behind the glove box.23. Check to see if the passenger door plunger is wired. If not, you'll know now it, and not freak out about it later.
24. Remove the box at the head of the center console. It has three harness connectors on the left, and they are labeled by color. Two clips and the box should come out.25. Make sure the gear lever is down in 1st, and the steering column is lowered in the tilt function.
26. Pull dash away from windshield. It will fall against it's own stop. Lift it up off the pins that it hinges on, and it will be free. If you are careful with it, you can take it out the passenger side as is. Help at this stage is awesome, though I put the dash back in myself.27. Pretty much anything in the middle that is black plastic is now coming out, but as one unit. The vacuum module in the front does not need to be disconnected. Let's start with the worst one: Inside the air box in the engine compartment is one of the bolts. There is a spot labeled "cut here for service." It's just to the left of the heater hoses. Cut that out with your utility knife. Not too deep, there is a plastic panel right below it.28 Remove three 5.5 bolts and remove cover. Some earlier models had a blower resister here.
29. With a ratcheting wrench or a 3/8" ratchet and deep socket, remove the one bolt in there which will be shoved up against the filter on the left. Be calm, take your time, it will be a while.30. Over to the right, there is one bolt holding this plastic box to the firewall. Remove it. Near the heater hoses is a stud that protudes from the firewall roughly an inch. Remove the nut.
31. Pull the hoses. You'll lose maybe a cup of coolant here.
32. Inside, passenger floor. At the top of the carpet under the box are three legs. The outside ones are threaded, and you can see the bolt head in them. It is on the engine compartment side. In the middle is one bolt you can remove.
33. On the two outside legs, most people, it seems, just cut them. I did. After bolting it all back together, I shook the unit hard and couldn't find a reason for them. At any rate, I cut the plastic above the bolts and left them screwed into the plastic.
34. Now the box should shake pretty easily. Don't forget that it sits on a saddle that feeds the floor heater ducts for the back seat. There will be a tiny bit of resistance here, but not too much. If there is resistance pulling this out, double check for bolts.
35. As you start to pull the unit out, look for vacuum or electical connectors that need to come out. Top right, there are two, I think. I had taken them all off, but found most could have stayed.
Now that the box is out, yank the two bolts on top of the heater core, remove it. If your foam is OK, reuse it. It holds the core nice and tight and keeps the warm air where it should be.
36. Rejoice! You are more than halfway done. I spent 6 hours removing and a little over 4 hours putting it back.
Good luck!