Air conditioning
 

We have a 95 Blazer that we have owned since 98. We have taken the blazer in twice to have the air conditioning fixed and after paying more than we would like to have, we were told that the plastic is falling apart around part of it and there was no fixing possible. I am wondering at this point if it is possible to replace the plastic parts that are brittle and breaking. I am assuming that is the issue since the last mechanic tried to tape it back together
https://cimg4.ibsrv.net/gimg/blazerf...c513af5a4.jpeg
Air conditioning unit?

It's very common on these, I see a lot of them in the same shape in our salvage yard.

It's commonly called the "evaporator housing", "evaporator core housing", or "evaporator case", and is made up of two halves (at least the parts that usually brake is the left and right half; there's a lower section too that's not normally an issue). I've seen them stitched back together with duct tape, silver aluminum tape, some sort of thick super sticky tape used for roofing, and even some people going the extra mile to wrap it in fiberglass. Keep in mind that if the evaporator ever has to be replaced (which is not super common), if one were to go the fiberglass all over it route, it would make the evaporator replacement a real pain...

I think the reason these are so problematic on the S chassis is because they're located under the hood with all the engine bay heat, which degrades the plastic and makes it fragile after years of heat cycles. On 99% of vehicles, this housing is inside the cab under the dash and they don't typically suffer the same fragile problem...

You could try to source another on in a salvage yard, but they can be a bear to remove, especially without breaking it even if it was all in one piece to begin with, just because of how fragile they've become over the years.

The original GM part numbers your looking for are 52474440 and 52475950. You can get them brand new from a few sources online (usually new old stock, because I'm pretty sure GM isn't actually producing them anymore...), and both halves together should cost less than $100. It's up to you though if you want to invest that into the repair or just patch it back together.


https://www.gmpartsgiant.com/parts/g...-52474440.html

https://www.gmpartsgiant.com/parts/g...-52475950.html

Thank you very much for the quick and informative reply. If our air conditioner does not work at this point, would this be the issue, or something else in the system? I know it worked for awhile after the mechanic worked on it, but probably only about 6 months or so. We hadn’t been driving the blazer too much at that time so it would sit sometimes for up to a month without being driven. The air conditioning would go even longer since winter would settle in. We want to start driving it more now and the lack of air conditioning is really the only big problem we have with it.

What exactly do you mean by it's not working? Is it now blowing any air? Does it only blow air on certain fan speed settings? Does it blow air from the vents just fine, just not cold air?

If only certain speeds are working, it could be an issue with either the blower motor resistor (in the case of only the highest speed setting working) or the high speed relay (if all speeds EXCEPT the highest speed works)
If no air at all is coming out of the vents, but you can hear the blower kicking on when you try to turn it on, it's possible that a blend door actuator has failed. It's pretty common on these for the actuator for the defrost vents to break, making the air only come out of the defrost vent up on the dash under the windshield.
If air is blowing out of the vents as it should, it's just not cold, then that's another scenario, and you would need to do some more digging. First thing would be to test the pressure in the system with a set of manifold gauges. If the system is low on freon, it will not engage the AC compressor, thus you will not get cold air.

But I also noticed in your picture that the pressure switch at the top of your accumulator is not plugged in. Not sure if you unplugged that for the photo, or if that's just how it was already. But with that unplugged, the system will NOT engage the AC compressor.


https://cimg1.ibsrv.net/gimg/blazerf...d179ed59b.jpeg

If you do go the fibetglass route, I highly recommed the literature available at the West System fiberglass/epoxy website.

And the Eagle Eye Award goes to blazen_red_4x4. Good catch.

And thanks for the part numbers on the housing. I'm going to file that away for when I need it.

I have a modest build thread but in it you can find my write-up on doing a full AC replacement. Unfortunately for your case, I was able to keep my evaporator and its housing was in good shape. But perhaps you might still find it useful.

Good Luck!

:icon_denk: