Got it out yesterday. What a pain in the rear that was. Didn't expect the wiring harness that goes under the middle consol. Not sure what that box does but it has wires that have to come off in order to pull the dash so I had to push the dash back up in place, put one screw in to hold it there, and remove the consol in order to disconnect the mystery box.

I have decided that every square inch of this vehicle has at least one wire running through it. Never have I seen such a mess of wiring on a vehicle before and it makes me really appreciate my old truck. Next Blazer I buy will have to be built in the 70's or 80's.

All that aside, hoping to get the core in today and hopefully if it doesn't start raining will get the dash back together. Be nice to have this turn into a two day project rather than spending the whole week on it.

 

Please post the pictures you have when you finish. That's the one thing I didn't do and wish that I did. It will be really great to supplement all the info in this thread with some nice pics. Particularly of the two bolts that everyone seems to have a problem with. as well as the harness with the blue forks "out".

 

THIS IS NUTS!!!!! One of the bolts that has to be removed in order to take out the plumbing/air ducts/whatever is located behind the AC coil. After searching for about an hour for what bolt was still holding this thing on I finally found it. Had to chop out part of the plastic cover to get to an access hole. If memory serves, this is the place that some models have a resistor or something. Anyways the plastic cover is dry rotted so it crumbled while trying to cut the access. Guess I will have to try and fix that when I go to put this thing back together.

After gaining access I see that my last bolt is located down in a hole that my hand or a wrench can fit in and the bolt itself is up against the AC coil. So even if I could get a wrench to it I would put a hole in the coil when the bolt begins to back out. SOOOOO It would appear I need to remove the AC! I am really beginning to HATE this vehicle.

Well back to work. Had to just take a break and try and cool down a bit after seeing this mess.

 

Definitely success, and anyone with a second gen, this actually was way easier than I expected. Don't worry about the book. I had the Haynes open and it really did nothing for me. This list got me through.

The job was time consuming, and there was one bolt I couldn't find on any suggestions but ended up being there ( right behind the distributor, it's the one that holds the corner of the heater box in the engine compartment.) I spent 30 minutes trying to get the floor heater channels out thinking that was what was holding me up. Nope, another bolt.

I will try to post pictures tonight. I have basically written a complete how-to for my 2001 with auto climate, with bolt sizes and pictures for pretty much the entire removal job. I spent 7 hours getting to the core, about 30 minutes transferring the foam to the new one and cleaning the box (make sure you clean it good!) and about 4.5 putting it all back together. 30 minutes of that was because I dropped the socket in the heater box. I had to have my wife come get it with her smaller arms.

If you have any immediate questions, post here or email me personally. I have most of it fresh in my mind.

Incidentally, two things that need attention: my push-button for the rear hatch isn't working now. It does outside in back, but not at the dash. Strange about this? It is one unit with the rear wiper which DOES work, and it's one harness. Maybe a fuse; but my wife has been driving it since I finished. Also, the drivers door plunger isn't working. The cabin lights do not come on when I open the door, and the radio does not turn off when I've reached my destination. Interesting part: I didn't touch the wiring for it; it came out with the dash. So maybe I disconnected it accidentally when installing the parking brake cable.

Now, the bolt in the, well, I call it heater box, but the one you have to cut into. That sucked, but I got it out. Here's what I did. First the ruibberized cover on mine, you cut it out, and then underneath there is an access panel. 3 5.5mm (I think) little bolts and out it comes. Inside, there is what I thought was a filter, not a coil. It was relatively movable. At any rate, the washer of the bolt inside there was under it a bit. I took a deep socket and a 3/8" wrench to the bolt in there. 10mm if I remember correctly. I could get one click on the ratchet, so I just took a deep breath and slowly started the bolt with a single click each throw (the handle of the ratchet had only that much room in the hole of the box.) After it started to get loose, I took the ratchet off and reached my hand into the hole. I'm 5'11" and 200 lbs, so you can get my size. I have a couple of cuts on my hand from this weekend, but I got my hand in, and wound that bolt out with just the socket. Surprisingly, I got it back in within an acceptable time frame, but when done, I accidentally dropped the socket trying to get my hand back out of the hole, and had my wife come in to retrieve it.

That box on the lower front with the three connections (behind the ash tray), yes, I took that one out after the fact, just like you. Never read anything about it, but it's important I suppose (though surprisingly light given the three major harnesses feeding into it.) By the way, the umbilical cord that runs into the center console? That's for the cassette on mine.

 

I find that it was easiest to get that bolt out with a long ratchet box wrench.

If there is anything you guys would want for Christmas, I Highly recommend crying for a ratchet wrench set. Best invention since the origional ratchet set.

 

I know my father-in-law is getting a set, from my wife. Hey! Over here! (Waving hand) I want one!

I do know this: I tried the small socket on the ratchet, and it wouldn't clear the filter/screen/whatever. It was just too close. The deep socket allowed the ratchet to get away from the screen far enough to function.

 

I am done. The bolt that appeared to be on a AC coil turned out to be some kind of mesh that is very flexable. Still could only turn a rachet about a 1/8 turn at a time. Took some time but did come out. Thought I had all bolts removed but found two more coming in from the engine side of the firewall. Never could see them on that side but could see that there was what appeared to be two brass bolts going into the box. Well by this time I was tired of messing around with the thing so I hunted like crazy and finally found my book. What a waste of time. The book was absolutely no help.

From what I have found on the internet and in my book it would appear that every year has a different way of mounting this thing and from this thread it makes me wonder if there are differences from vehicle to vehicle based on maybe options, engine size, etc. Nothing I have found matched up with what I found on mine.

Anyways, as I said I was getting pretty fed up with this thing and figured whatever the two bolts was holding on the engine side would be fine if I cut the plastic free from them. Out come my dremel and in a matter of about 1 minute the air box was free.

My foam on the heater core was pretty well rotted so I went with no foam. Figured I may sell this Blazer before long. It has been nothing but trouble lately and it is such a pain to work on. It makes me have nightmares about wiring. So far I have not found any part of this vehicle that doesn't have a wire running to it or through it.

In the end it is back together. Have several left over bolts including that annoyance in the AC hole. Yep didn't put it back in. Hands to big to fit in the hole and I wasn't about to spend another minute messing about with it. Got three mounting bolts on the box and it felt secure to me so the dash went back on. Tested it out and I have heat without any antifreeze smell and all my electronics appear to be working so overall I am very satisfied.

 

I'm glad you got it all back in! Enjoy the heat!

 

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 panel
3. Remove two 7mm bolts holding passenger lower panel
4. 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 dash
12. 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!

 

oh gawd......its getting into the high 30's here and i need to do it but i dont think i can. damn it.