1985 e350 Econoline - HVAC Problems
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Joined: Jun 2018
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1985 e350 Econoline - HVAC Problems
Hello Everyone - hope you can help me out
I have older 1985 Econoline with 6.9 Diesel.
The HVAC fan seems ONLY to work on AC, when I switch it to heater or defrost, the 3spd fan turns off. Fan works fine on the AC.
It WAS working on defrost/heat until I switched it over to AC.
As far as I can tell this is all cable driven. I think the plenum door changes OK, but cant verify without the fan working.
I am unable to find any diagrams, reference info - does anyone have diagrams on this damn plenum or an idea why the fan would turn off?
I did notice the slider control has a fan switch control on it - switch depresses on AC position, but not on heat or defrost.
Appreciate the help!
I have older 1985 Econoline with 6.9 Diesel.
The HVAC fan seems ONLY to work on AC, when I switch it to heater or defrost, the 3spd fan turns off. Fan works fine on the AC.
It WAS working on defrost/heat until I switched it over to AC.
As far as I can tell this is all cable driven. I think the plenum door changes OK, but cant verify without the fan working.
I am unable to find any diagrams, reference info - does anyone have diagrams on this damn plenum or an idea why the fan would turn off?
I did notice the slider control has a fan switch control on it - switch depresses on AC position, but not on heat or defrost.
Appreciate the help!
Thread Starter
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New User
Joined: Jun 2018
Posts: 4
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Problem fixed.
DIAGNOSIS
- Found that engine side (heater) fan not working on defrost/heat. There is an inside fan which runs when on AC - that works OK.
- wired fan motor direct - worked.
- used multimeter - found no power coming on to the engine side fan at the plug
- traced back to the heater control - found power at the plug at the HVAC control module.
- Cut and replaced the wire from the plug to the other plug, used but connectors and shrikwrap tubing to seal it up. NOTE: I drilled a hole passenger side through firewall and put in grommet for running new line (as per below)
- Wire was cut where it went in through the firewall beside the heater hose.
- now working
NOTE: When hvac unit on AC, the inner fan works and the engine side is disabled. The engine side works when the hvac unit is on DEFROST or HEAT.
ALSO,
Had a problem with the HEAT/COLD damper door slider cable - the cable clip broke at the HVAC unit.
Used a plastic tie and a hose clamp around the cable sheath to hold - managed to pull the cable in tight to the swing arm without a problem. Finding a cable at wreckers or ordering one - good luck
There you have it - in case you have this proiblem...
DIAGNOSIS
- Found that engine side (heater) fan not working on defrost/heat. There is an inside fan which runs when on AC - that works OK.
- wired fan motor direct - worked.
- used multimeter - found no power coming on to the engine side fan at the plug
- traced back to the heater control - found power at the plug at the HVAC control module.
- Cut and replaced the wire from the plug to the other plug, used but connectors and shrikwrap tubing to seal it up. NOTE: I drilled a hole passenger side through firewall and put in grommet for running new line (as per below)
- Wire was cut where it went in through the firewall beside the heater hose.
- now working
NOTE: When hvac unit on AC, the inner fan works and the engine side is disabled. The engine side works when the hvac unit is on DEFROST or HEAT.
ALSO,
Had a problem with the HEAT/COLD damper door slider cable - the cable clip broke at the HVAC unit.
Used a plastic tie and a hose clamp around the cable sheath to hold - managed to pull the cable in tight to the swing arm without a problem. Finding a cable at wreckers or ordering one - good luck
There you have it - in case you have this proiblem...
4th Gear
Joined: Apr 2023
Posts: 4
Likes: 3
From: Illinois
Problem fixed.
DIAGNOSIS
- Found that engine side (heater) fan not working on defrost/heat. There is an inside fan which runs when on AC - that works OK.
- wired fan motor direct - worked.
- used multimeter - found no power coming on to the engine side fan at the plug
- traced back to the heater control - found power at the plug at the HVAC control module.
- Cut and replaced the wire from the plug to the other plug, used but connectors and shrikwrap tubing to seal it up. NOTE: I drilled a hole passenger side through firewall and put in grommet for running new line (as per below)
- Wire was cut where it went in through the firewall beside the heater hose.
- now working
NOTE: When hvac unit on AC, the inner fan works and the engine side is disabled. The engine side works when the hvac unit is on DEFROST or HEAT.
ALSO,
Had a problem with the HEAT/COLD damper door slider cable - the cable clip broke at the HVAC unit.
Used a plastic tie and a hose clamp around the cable sheath to hold - managed to pull the cable in tight to the swing arm without a problem. Finding a cable at wreckers or ordering one - good luck
There you have it - in case you have this proiblem...
DIAGNOSIS
- Found that engine side (heater) fan not working on defrost/heat. There is an inside fan which runs when on AC - that works OK.
- wired fan motor direct - worked.
- used multimeter - found no power coming on to the engine side fan at the plug
- traced back to the heater control - found power at the plug at the HVAC control module.
- Cut and replaced the wire from the plug to the other plug, used but connectors and shrikwrap tubing to seal it up. NOTE: I drilled a hole passenger side through firewall and put in grommet for running new line (as per below)
- Wire was cut where it went in through the firewall beside the heater hose.
- now working
NOTE: When hvac unit on AC, the inner fan works and the engine side is disabled. The engine side works when the hvac unit is on DEFROST or HEAT.
ALSO,
Had a problem with the HEAT/COLD damper door slider cable - the cable clip broke at the HVAC unit.
Used a plastic tie and a hose clamp around the cable sheath to hold - managed to pull the cable in tight to the swing arm without a problem. Finding a cable at wreckers or ordering one - good luck
There you have it - in case you have this proiblem...
From what I can tell the fan speed selector runs a loom to the fan motors resistor. One of those wires from the fan speed selector runs to a ground. I thought it was the green and white coming to the other side of the climate control but it either is not it or the climate control center is bad.
Thanks...
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