Front Heater issue, can't find the trees in the bush... (3 Viewers)

[Reko]

Hey guy's,

It is horrible for me to ask, but the search function on the forum could not help me, I found only things that are aside my problem. (Have to say, I am not at all good in English, so that doesn't help neither in tech talk..)


My front heater doesn't work. Blower works, rear heater also.
The valve on firewall works, but not the stick that handles the valve. I have opened the valve manually but that does not help to put hot air in cabine.

I do have to say that I also have a problem with my lights in dashboard, presumably a fault ground problem, that's something I am trying to solve a few weeks already, but I can not connect the 2 problems.

Again, sorry if this question is already asked an someone given the answers, but I could not find it.

If something is not clear, please ask, I try to clarify my words
..



Tia, Koen

 

[voodu3]

This might help the electrical diagram for the heat and ac. Also check your fuses if you haven’t already. The system runs through the gauge fuse so if your dash and gauges aren’t working that’s a good place to start.

 

[Reko]

Thank you! Fuses were not checked yet, blowers and stuff all works. But when I get home, I check them!


Edit,

No fuses are blown..

 

[baldilocks]

What do you mean when you say the valve works but not “the stick that handles the valve? If you move the the lever arm of the valve to the open position and still get no heat in the cab then the valve must be broken internally.

Does the valve arm or the linkage move when you slide the in dash heat control to “HOT”?

As for your dash lights, is the dash light dimming rheostat turned down all the way?

 

[Reko]

Valve control arm is not moving when changing from hot to cold and vice versa.

Lights are flashing from about 1700 rpm till 2700 rpm...
Lights are brake, turbo overboost, coolant ...

 

[Broski]

Replace the control valve.
If that doesn’t help then then the heater core is mostly clogged.

 

[Reko]

Thanks already for the help!
I have flushed the heater core, had only clean water coming out. Only thing that bothers me more is that last month I had a damped interior, wet floor on passenger side and stinky smell....


Where is that control valve located? Near firewall under bonnet?

 

[Broski]

Should be on the fire wall if it's a 80

It's helpful if you post what you rig is !

You can put it you signature as well

 

[Reko]

Will do!

 

[60 toy ota]

Sounds like you have a blend door not actuating and a control valve servo that's also not working. Those are known to act up from time to time

 

[baldilocks]

Disconnect the actuator rod from the valve, under the hood centered on the firewall up high, and move the valve arm to open with your hand and see what you get inside the cab with the engine needs to at operating temp.

 

[Reko]

I have taken the valve of, was clean and working well.. could not blow threw when closed..


Thinking worst case is happening.. front core....

 

[Malleus]

Probably not the core, if you can get water into and out of it. If you can disconnect the wire to the heater control valve on the engine side of the firewall (it's near the top of the firewall, in the center), and open the valve and no heat comes from the dash vents, then it's mostly likely the blend door that is not moving. Download the A/C section of the FSM in the 80 series Resources section. That has the heater system operation, troubleshooting and repair instructions in it.

 

[bdog75]

I had the slide bar, the one from hot to cold go out on my control unit. It would not move the blend door from hot to cold.

 

[Mark W]

Probably not the core, if you can get water into and out of it.

Not completely true. If you are not familiar with the volume of flow that should pass through the core normally, it can be hard to recognize the reduced flow caused by core blockage.

I just posted this in the other thread that has been active in this discussion.

"It is not uncommon for the heater core to clog up. The front heater seems to be more prone to it than the rear. I acid flushed one a few days ago. Went from about 120* max temp measured at the dash vents running down the highway with outside temps in the 60 degree range to 220*+ with outside temps at 15* (got tired of burning my hand holding the sensor there and figured that was all I really needed to know. )
The rear heater was out doing the front significantly. Now it is lagging behind a bit, even though it is pulling air from within the cabin. I'll flush it the next time I am doing in maintenance on the rig."

And this.

" "water was as clean going in as coming out"... does not mean much. if the blockage would come out just from water flowing through the core... then it would not be blockage. It is hard solidified deposits that clog up the core. You have to dissolve those to clear them (dissolve and black flush with a bit of pressure ideally)."

Mark...

 

[Reko]

Great help!

 

[Reko]

Ok guy's,



My problem is found, not solved yet but found.



The cable to open and close the valve on the firewall is stuck. This means that the relay to open the air valves is also blocked . I removed the cable from the relay, located behind the glove box, opened the valve on firewall manually and now I have heat in front of the car.





The only thing that I have to do is to change the cable that goes from the relay to the valve.





I hope this is helpful to anyone, ans if there is anything not clear, please ask the questions!

 

[Squeegee]

I have the same issue. I just leave the valve open all year

 

[Reko]

I will replace the cable!

 

[Squeegee]

I will replace the cable!

Please do. Be better than me