Poor Heating '96 FJ80

[decoco]

If you did, it has a huge “auto” button & the temp/color-bar had nimbers in *F here (maybe *C up there, IDK) - otherwise you just have a blue to red colorbar with a blank button in the center of the CC box that does nothing.

Are you getting up to full temp (i.e. not a failed thermostat) - if you have full travel on your heater valve that or air in the system or a plugged core are the only things that come to mind.

Is your coolant remotely recent & not some mystery sludge, and are you seeing full operating/coolant temps?

Have you opened the system or replaced the heater valve?

you're correct, I have the non auto controls.


thermostat is newer (less than 2 years).
at the time did new rad, hoses , t stat and the grommet, heater valve and hoses replaced- heater worked fine.

heater was not strong prior, yet I had to change the rad a second time due to trail damage to the rad.

replaced, flushed as best as possible so there may be a little mixing of prestone and red.

important to note that the heater was not working properly prior to the 2nd rad change.

a flush may be a good idea anyway, yet unlikely to be the issue the way I see it- feedback is appreciated.

 

[decoco]

Drove today and used the scan gauge 86c which I think is about 187 f.

If this helps

 

[decoco]

Seems like this is a worthy cause Heater Core Flushing - OWNED!

 

[kilmarkid]

Having heater issues as well. 96 with 290k miles. Replaced the HCV, flushed the heater system and the heater core, removed the rear heater and replaced all heater hoses.

Here is the deal. When set in the cold position and fan on high, it blows a ton of air. When moved to hot, the airflow drops by 70% to 80%. It blows warm air for 2 minutes then gets less and less warm. The servo cable on the HCV works fine but I am guessing there is something wrong with the servo cable to the flapper and that is disrupting the airflow to the core.

I have also burped the cooling system with the filling system funnel and have replaced the thermostat. My scan gauge shows constant cooling temps so the thermostat is not the issue.

Where is the servo cable to the flapper located?

Thanks!

 

[izzyandsue]

Does the fan loose power or you can hear it blowing but no air comes out?

 

[BILT4ME]

Having heater issues as well. 96 with 290k miles. Replaced the HCV, flushed the heater system and the heater core, removed the rear heater and replaced all heater hoses.

Here is the deal. When set in the cold position and fan on high, it blows a ton of air. When moved to hot, the airflow drops by 70% to 80%. It blows warm air for 2 minutes then gets less and less warm. The servo cable on the HCV works fine but I am guessing there is something wrong with the servo cable to the flapper and that is disrupting the airflow to the core.

I have also burped the cooling system with the filling system funnel and have replaced the thermostat. My scan gauge shows constant cooling temps so the thermostat is not the issue.

Where is the servo cable to the flapper located?

Thanks!

When you replaced the HCV, What model, brand, part number did you use? There have been some that have installed the one they bought that is REALLY for a 92. It looks the same, but operates the opposite direction. You MAY have the wrong valve.

 

[izzyandsue]

This diagram may help find what you are looking for, the mix damper servo

HEATING & AIR CONDITIONING - HEATER UNIT & BLOWER | Toyota LAND CRUISER FZJ80L-GNPEKA FJ80,FZJ80 | Parts Catalogs | PartSouq

If you are looking for HEATING & AIR CONDITIONING - HEATER UNIT & BLOWER Parts for Toyota LAND CRUISER FZJ80L-GNPEKA FJ80,FZJ80 then we advise you to pay attention to the range of our spare parts catalog for Toyota!

partsouq.com

 

[kilmarkid]

Does the fan loose power or you can hear it blowing but no air comes out?

The fan keeps running at the same speed and continues to make the same amount of noise but the airflow drops.

 

[kilmarkid]

When you replaced the HCV, What model, brand, part number did you use? There have been some that have installed the one they bought that is REALLY for a 92. It looks the same, but operates the opposite direction. You MAY have the wrong valve.

I replaced the HCV 1st and the heater worked. Something happened since then.

 

[94txcruiser]

Thanks, I'll go and pull the radio this weekend and have a look!!
Cheers!

Wanted to see if you got a solve to this? Did the radio fix it or what was it?

Any advice here would be great...relatively inexperienced in mechanical work, but dont mind getting my hands dirty.

Warm air comes out in the back at the center console, great airflow out of the front vents - both when AC is set to hot or cold...AC does blow extremely cold. But when I turn to heat, no luck.

I was planning on checking the water control valve, mentioned above - then the foot vents / carpet to make sure that cable hasn't been disconnected.

Any other thoughts? or advice?

 

[wearsabrowncoat]

Wanted to see if you got a solve to this? Did the radio fix it or what was it?

Any advice here would be great...relatively inexperienced in mechanical work, but dont mind getting my hands dirty.

Warm air comes out in the back at the center console, great airflow out of the front vents - both when AC is set to hot or cold...AC does blow extremely cold. But when I turn to heat, no luck.

I was planning on checking the water control valve, mentioned above - then the foot vents / carpet to make sure that cable hasn't been disconnected.

Any other thoughts? or advice?

I had similar problems start of this winter. Turns out I had stuck thermostat. Didn’t notice it in the summer but when winter hit it took for ever to get coolant to warm up and never hot enough to get cabin heat. After switching thermostat problems solved. For reference it is 20 degrees in Cheyenne right now, scan gauge showing coolant temp at 182, and I am running heater at 75 degrees. Any Warmer and I would be sweating in here.

thermostat change out was somewhat of a pain. I had to borrow some crazy offset box end wrench to get the third bolt off (12mm I think). Once off it all went back on easy. The old thermostat didnt look bad but I didn’t run a test on it or anything but the new thermostat solved my lack of cabin heating.

 

[pawnthatdude]

thermostat change out was somewhat of a pain. I had to borrow some crazy offset box end wrench to get the third bolt off (12mm I think). Once off it all went back on easy. The old thermostat didnt look bad but I didn’t run a test on it or anything but the new thermostat solved my lack of cabin heating.

Did you take off the exhaust shield? The access is pretty easy with it off.

 

[wrxFTWdey]

Wanted to see if you got a solve to this? Did the radio fix it or what was it?

Any advice here would be great...relatively inexperienced in mechanical work, but dont mind getting my hands dirty.

Warm air comes out in the back at the center console, great airflow out of the front vents - both when AC is set to hot or cold...AC does blow extremely cold. But when I turn to heat, no luck.

I was planning on checking the water control valve, mentioned above - then the foot vents / carpet to make sure that cable hasn't been disconnected.

Any other thoughts? or advice?

I didn’t have heat for a year and a half. I replaced the heater valve at the firewall, flushed the heater lines and the core, nothing fixed my heat issue.

I was so fed up after I had to make a 2 hour drive in 18 degree weather with no heat. I’ve ridden in all sorts of military vehicles and even the majority of those have heat. I couldn’t take it anymore lol.

After some troubleshooting I learned that when I pressed and held the low-high buttons (pick one of them) with the setting on heat, the heat worked. As soon as I let go of the button, the heat stopped working and blew cold. I figured this was caused by an electrical issue. I could hear and see the arm behind the dash move when I pressed the button and it would move again as I let go of the button.

I took apart the AC control unit. Turns out the PO must’ve taken it apart to clean it or troubleshoot it. It has 4 screws holding it together on the back. In the process of removing those screws, I noticed that one of the corners of the motherboard was chipped off and the screw was actually below the circuit board(creating a gap). I assume that this is why when I held and pressed the button all the way in, it worked and held a good contact. There was a physical gap between the buttons and the circuit board behind it. Put it all back together even though the corner of the circuit board had a 1/4 inch chunk missing.

It’s been fixed for nearly a year and a half. The heat works so well now, that I have to keep it on low most of the time or it gets too hot and toasty.

I know this was a very specific issue, but I spent over a year trying to diagnose this issue. No one seemed to be in the same boat as me and their fixes didn’t help. Then again not everyone had the amazing PO that I do (pure satire and animosity of course).

 

[94txcruiser]

I didn’t have heat for a year and a half. I replaced the heater valve at the firewall, flushed the heater lines and the core, nothing fixed my heat issue.

I was so fed up after I had to make a 2 hour drive in 18 degree weather with no heat. I’ve ridden in all sorts of military vehicles and even the majority of those have heat. I couldn’t take it anymore lol.

After some troubleshooting I learned that when I pressed and held the low-high buttons (pick one of them) with the setting on heat, the heat worked. As soon as I let go of the button, the heat stopped working and blew cold. I figured this was caused by an electrical issue. I could hear and see the arm behind the dash move when I pressed the button and it would move again as I let go of the button.

I took apart the AC control unit. Turns out the PO must’ve taken it apart to clean it or troubleshoot it. It has 4 screws holding it together on the back. In the process of removing those screws, I noticed that one of the corners of the motherboard was chipped off and the screw was actually below the circuit board(creating a gap). I assume that this is why when I held and pressed the button all the way in, it worked and held a good contact. There was a physical gap between the buttons and the circuit board behind it. Put it all back together even though the corner of the circuit board had a 1/4 inch chunk missing.

It’s been fixed for nearly a year and a half. The heat works so well now, that I have to keep it on low most of the time or it gets too hot and toasty.

I know this was a very specific issue, but I spent over a year trying to diagnose this issue. No one seemed to be in the same boat as me and their fixes didn’t help. Then again not everyone had the amazing PO that I do (pure satire and animosity of course).

This is helpful insight

why would the "arm" move when you hold the high low down...shouldnt it move when you move the temp gauge from cool to heat?

 

[wrxFTWdey]

This is helpful insight

why would the "arm" move when you hold the high low down...shouldnt it move when you move the temp gauge from cool to heat?

Sorry I should’ve been more specific. I’m referring to the blend door(I think that’s what it is called) behind the dash. So there are two separate cables for the heat/cold. One of the cables connects from the inside of the dash to the firewall heater control valve. The other goes from the same point in the dash to what I assume is the blend door.

Even when I disconnected the cable on the firewall and manually set the valve to the heat position, the heat wouldn’t work because the blend door in the dash was always set to the cold position regardless if I had it all the way set red/heat. I have a video that I can send you if you need.

 

[94txcruiser]

Sorry I should’ve been more specific. I’m referring to the blend door(I think that’s what it is called) behind the dash. So there are two separate cables for the heat/cold. One of the cables connects from the inside of the dash to the firewall heater control valve. The other goes from the same point in the dash to what I assume is the blend door.

Even when I disconnected the cable on the firewall and manually set the valve to the heat position, the heat wouldn’t work because the blend door in the dash was always set to the cold position regardless if I had it all the way set red/heat. I have a video that I can send you if you need.

Yes please!!!

A video would be extremely helpful so i know what I am looking at when I take the dash off.

I checked the firewall control vale and when the AC is fully on its almost all the way to the stop, and when its fully on heat, its almost all the way withdrawn.

I couldnt find the "heater control arm" as mentioned on the first page, but I intend to look this evening.

Can you send me the video in a private message or post a link to it?

 

[wrxFTWdey]

Yes please!!!

A video would be extremely helpful so i know what I am looking at when I take the dash off.

I checked the firewall control vale and when the AC is fully on its almost all the way to the stop, and when its fully on heat, its almost all the way withdrawn.

I couldnt find the "heater control arm" as mentioned on the first page, but I intend to look this evening.

Can you send me the video in a private message or post a link to it?

Sure thing, when I get home I can upload it to YouTube and link you. Hopefully it’ll be helpful to others as well.

 

[wrxFTWdey]

Yes please!!!

A video would be extremely helpful so i know what I am looking at when I take the dash off.

I checked the firewall control vale and when the AC is fully on its almost all the way to the stop, and when its fully on heat, its almost all the way withdrawn.

I couldnt find the "heater control arm" as mentioned on the first page, but I intend to look this evening.

Can you send me the video in a private message or post a link to it?

Here you go brother. You can hear the clicks when I push the low-high buttons and you can see the arm moving behind the dash. It moves the second that I push the button and then reverts back.

 

[wearsabrowncoat]

Did you take off the exhaust shield? The access is pretty easy with it off.

No

 

[94txcruiser]

Here you go brother. You can hear the clicks when I push the low-high buttons and you can see the arm moving behind the dash. It moves the second that I push the button and then reverts back.

Man this is awesome - gives me some great clarity to what the mechanism is that needs to move to open (allow) heat to flow in.

Yours was electronic with the high / low switch, you mentioned your fix there. Ill check mine and see - but am afraid thatd be too easy...did you have to take the whole dash off to see those componets?