Heating Problems 88 5KSQ

[Ameer Antar]

I believe there's only one valve which controls water flow to the heater core, but there's also a flap inside the heater box that controls whether the air from the fan goes through or around the heater core. This will effectively turn off the heat if stuck in the wrong position. The flap is controlled machanically by a servo motor in the A/C programmer (near the ECU in pass. footwell). The servo motor can be separated from the black temp control cable if there's something wrong w/ the motor or climate system. The heater cable can be adjusted by pulling in or out to the proper heat settings. Since it has a spring return, you may need to lock it down w/ washers, a nut and bolt. That can be a temporar fix till you figure out what's happening. I've noticed that old heater cables can be difficult to move in it' full motion range, which can cause the servo motor to strip gears or burn out. I would replace any questionable cables, b/c it's much cheaper to replace  that than any of the climate control components... Good luck.

-Ameer

---Original Message---
Date: Sun, 14 Dec 2003 12:08:49 -0600
From: "B1biker" <b1biker at neb.rr.com>
Subject: Heating Problems 88 5KSQ
To: <quattro at audifans.com>
Message-ID: <019c01c3c26d$535f3c80$b4ee1f41 at dhaopooh>
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With the onset of cold weather here in Nebraska I'm having trouble getting the heater to work properly. I have changed the thermostat and checked the operation of the programmer, it seems to be working properly. The reicrculating flap is broken and in the 'fresh air' position but its been that way for several years and I have not had this problem in the past. My primary questions relates to the temperature control valve(s). The Bentley seems to indicate that there is only one temperature control valve in the system; this being the vacuum control valve located in the engine compartment. 
1 -- Is this valve open (full flow) position when vacuum is applied? (lever moves up and down freely in response to vacuum)
2 -- What is the likelihood that the valve is broken internally and is always partially closed even though it 'appears' to be working? 
3 -- Is there another valve that controls water flow to the heater core? If so where do I find it?

Any help will be greatly appreciated.
Gary L. Meier
82 CGT, 84 4KS, 88 5KSQ

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