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-   -   71 blazer heater/defrost box (https://67-72chevytrucks.com/vboard/showthread.php?t=756185)

chevyguy_72 02-02-2018 12:20 AM
71 blazer heater/defrost box
 
3 Attachment(s)
Anyone seen a box like this? The left side looks different than any I have seen before...

hemi43 02-02-2018 09:48 AM
Re: 71 blazer heater/defrost box
 
Looks like "heater delete" option.

chevyguy_72 02-02-2018 01:22 PM
Re: 71 blazer heater/defrost box
 
Quote:
Originally Posted by hemi43 (Post 8176263)
Looks like "heater delete" option.
There is a flapper inside of that box and a slot cut in the bottom and each corner... You can kinda see them in the pics...

hemi43 02-02-2018 11:25 PM
Re: 71 blazer heater/defrost box
 
Quote:
Originally Posted by chevyguy_72 (Post 8176431)
There is a flapper inside of that box and a slot cut in the bottom and each corner... You can kinda see them in the pics...
Yeah, but there's no fan. Even with heater delete, laws back then still required some sort of defrost. Even vehicles with heater delete, will still have a heater core. Not sure how GM did it, but I'm familiar with Mopars of the 60's

chevyguy_72 02-05-2018 12:29 PM
Re: 71 blazer heater/defrost box
 
Quote:
Originally Posted by hemi43 (Post 8176868)
Yeah, but there's no fan. Even with heater delete, laws back then still required some sort of defrost. Even vehicles with heater delete, will still have a heater core. Not sure how GM did it, but I'm familiar with Mopars of the 60's
Theres not a fan under there either way...
The fan is on the firewall next to the heater core...
The only thing under there is the box with all the flappers.

GMC-YA68 02-05-2018 12:58 PM
Re: 71 blazer heater/defrost box
 
Yea, but if you put a fan on the firewall, then turned it on...where is it going to blow? - not in that box because it's not connected to it in any way.

chevyguy_72 02-05-2018 06:16 PM
Re: 71 blazer heater/defrost box
 
Quote:
Originally Posted by GMC-YA68 (Post 8178843)
Yea, but if you put a fan on the firewall, then turned it on...where is it going to blow? - not in that box because it's not connected to it in any way.
Not sure what you mean here?
This has the same engine bay heater core/fan unit... i was just showing the first pic to show that its a non AC unit...
The stock located fan will blow through the heater core and into the cab portion of the heater box... my only question is the reason for the different shaped unit that disperses the heater and defrost.

hemi43 02-05-2018 06:50 PM
Re: 71 blazer heater/defrost box
 
Quote:
Originally Posted by chevyguy_72 (Post 8179062)
my only question is the reason for the different shaped unit that disperses the heater and defrost.
Like I mentioned before, most likely it had "heater delete" option.

chevyguy_72 02-06-2018 12:08 PM
Re: 71 blazer heater/defrost box
 
Quote:
Originally Posted by hemi43 (Post 8179087)
Like I mentioned before, most likely it had "heater delete" option.
Sorry but that doesn't make sense to me since it actually has heater ports on the bottom and sides? A delete to me would be no heater at all... maybe just a defrost unit... this still has both and a flapper inside to control between them with all 3 wires and the same controls as the other unit...

cleszkie 02-06-2018 01:46 PM
Re: 71 blazer heater/defrost box
 
Whatever you have there apparently did not come with that truck because I can see the mounting holes where the original box was mounted. Are there provisions for a heater core inside the box, or any sign of openings that heater hose could have been routed into? Otherwise that box is pretty much worthless as a defrost without a fan, and worthless as a heater without a fan and source of heat.

chevyguy_72 02-06-2018 05:14 PM
Re: 71 blazer heater/defrost box
 
Quote:
Originally Posted by cleszkie (Post 8179747)
Whatever you have there apparently did not come with that truck because I can see the mounting holes where the original box was mounted. Are there provisions for a heater core inside the box, or any sign of openings that heater hose could have been routed into? Otherwise that box is pretty much worthless as a defrost without a fan, and worthless as a heater without a fan and source of heat.
The stock engine compartment unit is there and ready to bolted on... it contains the heater core and fan is identical to every non ac one i have ever seen in these trucks... the only different part is the air deflector portion that directs air to the defrots vents or the floor...


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