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-   -   A.c. and heat issues (https://blazerforum.com/forum/lighting-electrical-52/c-heat-issues-95367/)

Griffith94 Sep 20, 2017 05:27 PM

A.c. and heat issues
 
Ok I replaced the a.c. compressor the a.c. control module the orfic tube the blower motor the resistor drained the Freon and refilled to spec. And now the a.c. cuts in and out on heat both. It will run and than shuts off completely I can't even switch to heat or anything it won't come back on for about 10 mins and than comes back on. Please help me I'm trying to take a trip with my wife and 2 month old son but can't in the heat i need to get the a.c. working and the heat. It's a 1996 Chevy blazer LS 4 door it has the 4.3 vortex motor and it's 2 wheel drive

blazen_red_4x4 Sep 20, 2017 08:44 PM

Is this only on the high speed setting possibly? The high speed relay is known to go out and can cause the system to just stop working, and then when the relay cools down it'll start working again, then the process will repeat. But all other fan speeds will work fine.

These trucks, specifically as they get older (2000 an older seem to be most common), have issues with the vacuum line rotting that runs into the cab. All of the AC ducting actuators in the dash that control the temp and where the air flows to is worked by vacuum actuators. If that line rots the system loses vacuum and nothing works.

What are you referring to as the "ac control module", the actual controls in the dash?

Is this the manual style AC were you just have a blue and red arch around the dial on the far right of the controls or is it the auto style with actual temperature numbers around the dial on the far right of the controls?

Griffith94 Sep 20, 2017 08:49 PM


Originally Posted by Griffith94 (Post 680397)
Ok I replaced the a.c. compressor the a.c. control module the orfic tube the blower motor the resistor drained the Freon and refilled to spec. And now the a.c. cuts in and out on heat both. It will run and than shuts off completely I can't even switch to heat or anything it won't come back on for about 10 mins and than comes back on. Please help me I'm trying to take a trip with my wife and 2 month old son but can't in the heat i need to get the a.c. working and the heat. It's a 1996 Chevy blazer LS 4 door it has the 4.3 vortex motor and it's 2 wheel drive

It's on all settings and yes it's the manual kind with blue and red. And the control module that I'm talking about is in the dash correct I've checked all relays and fuses and everything is good and it still does it on all settings high and low cold and hot

Griffith94 Sep 20, 2017 08:51 PM


Originally Posted by blazen_red_4x4 (Post 680400)
Is this only on the high speed setting possibly? The high speed relay is known to go out and can cause the system to just stop working, and then when the relay cools down it'll start working again, then the process will repeat. But all other fan speeds will work fine.

These trucks, specifically as they get older (2000 an older seem to be most common), have issues with the vacuum line rotting that runs into the cab. All of the AC ducting actuators in the dash that control the temp and where the air flows to is worked by vacuum actuators. If that line rots the system loses vacuum and nothing works.

What are you referring to as the "ac control module", the actual controls in the dash?

Is this the manual style AC were you just have a blue and red arch around the dial on the far right of the controls or is it the auto style with actual temperature numbers around the dial on the far right of the controls?


Manual setting with blue and red. It's happens all all speeds high and low and such. Relays and fuses are good but cuts off for about 10 mins and than comes back on and does it over and over. Idk what else to look for. And the control module I'm talking about is in the dash correct.

MountainDew Sep 24, 2017 08:58 AM

Im having trouble following what exactly the problem is but from what you have replaced and what I know is the most common thing that screws up is the Blower Motor Control Module-Resistor. This thing
https://cimg4.ibsrv.net/gimg/blazerf...629fea0e9f.jpg

its out in the engine bay mounted next to the heater blower motor.

if this is something you already replaced my bad.. so many modules, relays it is easy to mix things up.


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