What a piece of crap. 2002 Blazer. Have taken out dash and everything else even tire and inner fender. Removed bottom 2 bolts hidden by fender but still seems to be hanging up on the fender side. Seems to be another bolt somewhere... hate to say it but it seems to be under a/c box...please say no! Any ideas. Why do they make it sooo hard to change something as simple as water heater. The frigging engineers need to work as a mechanic for 5 years to see why simple things take so long to repair....Bet your *** they would change things. Come on...take tire and fender well out along with the dash to change heater...morons!! Sad is they make the biiiig bucks while we just get by! Thet must wake up and say what service tech can i make life terrible today and cost the car owner their first born.

Any help Thanks guys
Frank

 

I just did the core on my 99. I had to take out 6 screws and bolts to get the heater module out. They are:

1,2: behind the passenger's inner fenderwell. These also hold on a heat shield.
3: Inside the cab, at the bottom of the module, quite near 1 and 2.
4: Under the hood, to the driver's side of the distributor on the firewall.
5: Under the hood, behind the transmission dipstick on the firewall.
6: This is the clinker. On top of the AC box under the hood, there's a blower motor resistor. Look for the electrical connector on top. Unplug it and cut through the rubberized coating on the AC box to expose the resistor. You should be able to make out it's hump/outline. It's held in by 3 screws. Now with the resistor removed, there's a screw down inside the well of the AC box. I believe the dealers do this job by removing the AC box, along with whatever else to get to the AC box, but my Haynes manual said it could be reached through the resistor hole

If you don't already have them, hit a tool store and pick up a t-handle speed ratchet, some universal joints, and some extensions. They'll be your best friends during this job, especially if you got big ham hock hands like I do.

This job isn't really as tough as many people make it out to be. It's just tedious due to the sheer amount of stuff you have to take off the truck just to get to the part to be replaced.

One other thing. While you got that heater module out, take the time to make sure it's operating properly. The blend doors on these trucks are notoriously fragile. Not only did I find one of mine broken, I also found a piece of the original one that broke 10 years ago when the dealer covered it under warranty. I went so far as to make sure all doors were intact, greased with silicone, and their vacuum servos inspected. I think the door cost me like $25 at a dealership. Might as well since you can easily get to them right now.

And I'll disagree with you on one thing though. These trucks weren't designed by engineers. They were designed by accountants and shareholders.

 

How-to heater core flush...
click here: https://blazerforum.com/forum/members/2000blazerlt4wd-31232-albums-how-heater-core-flush-2555/

 

That last one was a kicker for me, I was mad and just ripped at the box till it broke. Fixed it once it was out.

Justin