Author Topic: Heater control cable adjustment?  (Read 1218 times)

X33RS

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Heater control cable adjustment?
« on: January 02, 2017, 06:16:51 PM »
The AIM is showing nothing that I can find.  I've had the dash apart 3 times now looking for something that I'm guessing isn't there.
  My issue is the fan control switch.  It acts as though the cable is too long.  As I pull it down I get low and medium speed, but I have to force the switch down further for high speed, and then the cable pushes the switch back up to medium.
 
Cable moves freely, and I can reach the air door that it controls down on the box, it's moving the door to the end of it's travel before I can activate high speed on the fan, so it's keeping the control lever from moving further.  It's almost as if the cable is too long, and I see no adjustment on it anywhere.  I only have to push the control switch down about a 1/2" more for high speed to engage, yet the lever is no where near the bottom of the control panel.

I see no adjustment.....thoughts?

Rufcar

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Re: Heater control cable adjustment?
« Reply #1 on: January 03, 2017, 01:23:50 AM »
I have same problem in my 69 only have 1 speed and cable appears to want to move further down but cant. Its on my winter repair list.

X33RS

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Re: Heater control cable adjustment?
« Reply #2 on: January 03, 2017, 01:01:12 PM »
There doesn't seem to be a solution.  I looked at it again yesterday.  I can unhook the cable at the door and the lever moves fine and I can engage the high speed fan no problem.  Hook the cable up and the door hit's it's maximum allowed movement before I can move the lever far enough to engage high speed on the fan.

When I look at the cable, it still has room to go as it pulls the door, it's the door that stops, and it's fully open before the lever gets to high speed.

I tried installing a new switch mounted up behind the controls, hoping that the switching movements in the original might be a little worn and I might get lucky with a new switch.  It did help to a degree, as I can push the switch further down about a 1/2" and hit high speed, but I let go and it moves back up to medium speed on it's own.   When I watch the cable and the door while doing this, it's actually trying to pull the arm on the door further than it wants to go.  So the cable isn't too long or too short, it still has room to go. 

Unfortunately I see no adjustments anywhere, which seems odd to me.

69pace

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Re: Heater control cable adjustment?
« Reply #3 on: January 03, 2017, 05:52:00 PM »
Just to rule it out I would also double check that the cable in question is the correct one (length) for that slider. Double check that the sheath tab is secured in the right location as well.

I have a NOS set someplace for a 69 I can measure if you need.
1969 Z-11 350/300 with 4 Speed
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BillOhio

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Re: Heater control cable adjustment?
« Reply #4 on: January 03, 2017, 09:47:20 PM »
I am not sure why Larry is worried about the heater working where he lives??
1969 Z28, Burgandy, numbers matching, 12,900 miles
1967 Plymouth GTX Hemi, 4 speed, dana
1961 Chrysler 300G convertible

69Z28-RS

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Re: Heater control cable adjustment?
« Reply #5 on: January 03, 2017, 10:49:13 PM »
Perhaps he needs it when he is drag racing, he turns his heater up to HIGH and high speed fan to help take heat from the engine coolant...  :)

Don't we all do that???  :)
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
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X33RS

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Re: Heater control cable adjustment?
« Reply #6 on: January 03, 2017, 11:01:22 PM »
When it gets below 70 it's cold here  ;D

BillOhio

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Re: Heater control cable adjustment?
« Reply #7 on: January 04, 2017, 12:24:41 AM »
😂
1969 Z28, Burgandy, numbers matching, 12,900 miles
1967 Plymouth GTX Hemi, 4 speed, dana
1961 Chrysler 300G convertible

PURESS

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Re: Heater control cable adjustment?
« Reply #8 on: January 04, 2017, 01:43:41 PM »
it's only 7 below this morning

Kelley W King

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Re: Heater control cable adjustment?
« Reply #9 on: January 04, 2017, 02:27:57 PM »
I have two 69,s. Both control work but not like I think they should. Both seem to be spring loaded near the bottom.
69 Z28 RS Scuncio Hi Performance
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X33RS

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Re: Heater control cable adjustment?
« Reply #10 on: January 04, 2017, 07:52:50 PM »
Well I found the problem.  I got out there early this morning and pulled the heater box out, seats, console, dash pad and glove box.  Got a good look at the cables and compared to the AIM.

Apparently way back in the distant past someone had crossed 2 cables up at the controls.  You can't cross them at the heater box because they only go one there one way.   But there are 2 cables on the controls that can be switched.  Someone crossed the fan control cable with the defrost cable.  Turns out that defrost door at the box has a very short movement which didn't allow my fan switch to move low enough to catch high speed.   The fan switch cable goes to a fresh air door in the middle of the box which has a rather large movement.

Once I switched the cables at the control unit my fan switch practically fell to the bottom when I pushed it and I had high speed on the fan.  All works nicely now.

Got it all back together now, just have to top off the antifreeze.

Rufcar

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Re: Heater control cable adjustment?
« Reply #11 on: January 05, 2017, 12:51:10 AM »
How far down does the switch go now? Mone only goes half way. I may have same symptoms. DI'd you change the cables at the heater side only?

X33RS

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Re: Heater control cable adjustment?
« Reply #12 on: January 05, 2017, 02:58:41 AM »
My fan switch goes all the way to the bottom now and makes a final "click".  The fan switch has a full range of motion from top to bottom.  It also works correctly, opening the fresh air door before the fan kicks on (where it says "air" at the top of the switch)

I didn't change any of the cables on the heater or "box" side.  I assume that's what you mean.  I did pull it all apart to have a good look at it though.  The cables on the heater box cannot be mixed up. 

The middle connection, which is the cable that runs to the fan switch, has a fixture on the cable and mounts on a bracket attached to the box, it will only mount in that location.

The far right connection at the box (passenger side) is heat control, and that cable is so long you can't mistake it for any other connection.

The far left connection at the box (by the gas pedal) is the defrost cable.  It's so short it wouldn't even reach the driver side.  So you can't mess up the connections on the heater box if you tried.

However, there are 2 cables at the switches that can be reversed.  The 2 outers switches (fan and defrost) are interchangeable with attachment points made exactly the same and can be reversed 180 and fastened to the other side.  That's where I found the issue.  The blower motor switch had the defrost cable connected to it, and the defrost switch had the fresh air door cable connected to it.  One door on the box moves a lot more than the other, hence the reason my fan switch wouldn't move it's full range.  Also defrost wasn't working either but I had not discovered that until now because I was more concerned with the blower motor initially. 

 The center cable at the switches cannot be connected anywhere but the center switch (heat).  It's made differently and won't properly attach to the other switches.

So at some point in this cars life someone swapped those cables, probably by accident.  It's been sitting dormant for 30 years and never driven so the issue wasn't found until now.

Rufcar

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Re: Heater control cable adjustment?
« Reply #13 on: January 05, 2017, 11:38:17 AM »
Thank you for that great explaination. I have my car on my drive on lift ready so it's the next item to be worked on since I can't seem to solve my rf brake lock up 100%.
Tkx again.