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Put new T'stat in 2 weeks ago. getting colder so heat would be nice.
I get no heat when I move lever to select heat. But if I leave lever to off and heat all the way to hot, I can feel some heat coming in. But I can not turn fan on as it will dilute the heat and blow cold.
Sounds to me like the cable from the temp slider lever has come disconnected from the lever or the crank arm on the heater box end.
I had that happen on my '92 recently; the crank arm actually popped up and out of the box, off the blend-door shaft. The crank arm was just laying on top of the heater box.
Sounds to me like the cable from the temp slider lever has come disconnected from the lever or the crank arm on the heater box end.
I had that happen on my '92 recently; the crank arm actually popped up and out of the box, off the blend-door shaft. The crank arm was just laying on top of the heater box.
Just drove it. Heat is getting to the heater box as there was heat in the cabin, so both hoses were hot. Have a 200 deg. T'stat in it. Ambient temp is 50 deg. and cabin was getting plenty warm with selection lever off and heat set to 1/2 way to full hot.
I'll have to look closer at it this weekend when it gets near 60 here in NC.
'84 heater control is pretty simple (as should be expected in a "basic" car). With the temp slider (bottom lever) full to the left (off), there should be no coolant flowing thru the heater core. Verify that the vacuum solenoid valve on the heater core is pulled in (engine running).
When the temp slider is moved away from the LH position, the coolant should flow thru the heater core. The vacuum valve at the heater core is "on".
Moving the temp slider right or left controls the door in the heater to vary the amount of hot air and cool air that mixes in the outlet ducts. Super simple!
The top lever selects where the warm/cool air is to be directed.
Note to OP: Tom400 (#4) and Cjunke (#9) may be right. Check that first. If the vacuum solenoid on the front of your heater box isn't working, there's a fix for that, too.
Note to OP: Tom400 (#4) and Cjunke (#9) may be right. Check that first. If the vacuum solenoid on the front of your heater box isn't working, there's a fix for that, too.
Have you checked the cable connection to the temp control damper under the dashboard on the pass. side? There are several of us trying to help you, but you need to respond to our suggestions.
Originally Posted by Hot Rod Roy
Verify that the vacuum solenoid valve on the heater core is pulled in (engine running).
When the temp slider is moved away from the LH position, the coolant should flow thru the heater core. The vacuum valve at the heater core is "on" (solenoid lever out).
Have you found the heater vacuum solenoid valve? It's located on the front of the heater-a/c housing under the hood.
At lunch I drove to town. On way back I tried the heat in normal position, IT WORKED!
So maybe valve was stuck and freed up, but I will check valve this time by looking to see if it moves.
Thanks.
71TTop
Found out yesterday that the lever arm that is screwed into the valve is very rusty. So I lubed it. Then the screw came out due to the rust had eaten away at the mounting hole. So now the lever arm needs to be remounted so it can work.
At lunch I drove to town. On way back I tried the heat in normal position, IT WORKED!
So maybe valve was stuck and freed up, but I will check valve this time by looking to see if it moves.
Thanks.
71TTop
I attached the lever arm to the solenoid and to the valve. Everything works fine. But NOW I see that the valve is leaking where the arm attaches, thus this is what caused the rust to form in first place.
Is there any fix for this or do I have to find a new valve?
Belairbrian and Whalepirot have identified the right part, but there are alternatives for this expensive part. Some have successfully rebuilt their heater valve by carefully extracting the core out of their original valve, and installing the core from p/n 74800. I was planning to do this mod, but when I figured out how the 74800 valve works, I found that I could use the entire valve as-is, to replace my original valve! Here's a link to my procedure. The hoses are even the correct sizes!
11-21-2017, 03:04 PM
'84 no heat
Good point.
