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No Heat Inside Cabin

Old 01-23-19, 09:28 AM
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No Heat Inside Cabin

I know this has been covered but I have yet to find my answer in the numerous threads I have read.

I have no, to very little heat, coming out inside my car. This issue came up a year or so ago but I never worried about it as its a fair weather car.

First off, the heater core is NOT plugged and the system is fully purged of any air. Both hoses are hot going into the core.

I am assuming this is a blend door issue, anyone know where this is? Picture or diagram would be great. Would the dash have to be removed to access it and change it if needed?

I did read that the FD is designed to not have heat come out of the face level vents, is this true? Ether way, I have very little heat coming from the foot and defrost areas as well. Coolant temps around 180-190.

Thanks.
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Old 01-23-19, 10:55 AM
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You are right, the FD is supposed to only duct heat to the floor vents.

In general, the FD's heater isn't amazing for whatever reason. The FC's heater would run you out of the car in short order.

There is a blend door and I have heard of the actuator going bad. I think the actuator can be accessed with the heater core in the car. Hopefully so, you have to fully remove the dash to get to the heater core.

With the car on but the engine not running you should be able to hear the blend door move when you change the temp select dial.

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Old 01-23-19, 03:34 PM
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You can access the actuator without removing the dash or the heater core. It's held on by three screws as I recall, with two being very accessible, and one a bit more difficult to reach as it is tucked close to the center tunnel. I think I used a shorty screwdriver to get to that one. You first remove a cover to access the unit.

Like Dale said, you can turn the car ignition (not engine) on and then move the temp control ****. When you do this, you will hear the actuator moving. I found it best to do this with the help of someone else working the temp control ****. If you can't hear it moving, then **** switch wiring or the actuator is bad. I had this problem a few years ago, and found that by removing the actuator and cleaning it solved the problem. However, I sadly note I too again have the issue and will be going back under the dash to diagnose.

Attached is the troubleshooting process for the air mix actuator and the temp control switch.

Finally, my FD (94) might be different, but heat comes out of all vents, including the face level vents. Works just like the AC does. The "mode" control **** controls this for both the heat and the ac.



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Old 01-25-19, 09:13 AM
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Thank you for the reply everyone. I, too, thought that heat was coming out of all the vents before it stopped working.

I will do some trouble shooting and report back.
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Old 01-25-19, 09:41 AM
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From what I can tell the blend door would be under the heater core area correct?

I have a OEM A/C Evaporator delete which I had thought maybe caused my issues as the blower would not have a more direct path through the heater core. I think that was debunked as no matter the speed the "heat" is warm at best.
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Old 01-25-19, 09:47 AM
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So there is both an air intake actuator and an air mix actuator. I can see the air mix actuator move when i turn the temp dial. Its easy to see from the driver's foot well. But i still do not get heat in the footwell.

However, when i run through the gears i get an occasional spurt of hot hair on my feet. Almost like the higher RPM is making the coolant move better.... its kinda hard to explain.

I have gone through 90% of my rx7 in the past 8 years, but i refuse to go behind the dash. Mainly if that shitty plastic breaks, its really expensive to replace and having great interior plastics adds real value to the car... in my eyes anyways.
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Old 01-25-19, 10:47 AM
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I had the same issue. You DO NOT need to take apart the dash to get to the hot/cold actuator. Even better... you probably don't even need to buy anything if you already have a soldering iron!

It's really easy to troubleshoot the actuator once you get the cover off. If it works, it will change positions when you turn the ****.

Check this thread for some photos:
https://www.rx7club.com/3rd-generati...ators-1066668/

Your heat during acceleration may just be the warmer air from the hot core getting past the blend doors and old weatherstripping. I always get better heat after spirited driving.

Last edited by alexdimen; 01-25-19 at 10:51 AM.
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Old 01-25-19, 12:38 PM
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Doing a reverse flush and a chemical flush of the heater core can help. They seem to really plug up.

That AC delete duct is a rare part!

Dale
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Old 01-25-19, 03:37 PM
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Originally Posted by DaleClark View Post
Doing a reverse flush and a chemical flush of the heater core can help. They seem to really plug up.

That AC delete duct is a rare part!

Dale
Good to know, I can add that to the list of things to try.

I actually ordered it right from my local dealer. When I ordered it they said it was the last one in North America. That was back in 2016.
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Old 01-25-19, 03:43 PM
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Originally Posted by alexdimen View Post
I had the same issue. You DO NOT need to take apart the dash to get to the hot/cold actuator. Even better... you probably don't even need to buy anything if you already have a soldering iron!

It's really easy to troubleshoot the actuator once you get the cover off. If it works, it will change positions when you turn the ****.

Check this thread for some photos:
https://www.rx7club.com/3rd-generati...ators-1066668/

Your heat during acceleration may just be the warmer air from the hot core getting past the blend doors and old weatherstripping. I always get better heat after spirited driving.

This is super helpful, thank you!
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Old 01-25-19, 07:10 PM
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i had the same issue for years.
i solved it last month by making a reverse flush of the core with a hose and water.
a lot of gung and rust came off the core and now i have hot air :-)
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