Full Heat at All Temperature Settings (Pre-1985.5 944s and All 924s)
On the early 944s pre-1985.5 full heat problems are somewhat unusual. However, when it happens, it is normally caused by the bowden cable for the heater unit damper coming loose. This will be much easier said than done but, you'll need to locate the bowden cables on the back of the heater controls on the center console and follow them until you locate the correct damper. There should be three cables. One for the heater unit damper, one for the AC unit damper, and one for the heater control valve (the heater control valve cable will go through the firewall). The damper for the heater unit is behind the center console. And, the AC unit damper is on the passenger's side of the vehicle. So, locate the cable for the heater unit damper and see if it is disconnected or broken.
Full Heat at All Temperature Settings (1985.5 and Newer 944s)
On late model 944s (1985.5 and newer), there are several problems that can cause the full heat condition. The first and most common problem is a damper linkage in the driver's side footwell (for left-hand drive cars). Stick your head in the footwell and look up and toward the center console. You should see a small diameter metal rod which rests in a white plastic support and is held in place by a metal retaining clip. On later model 944s, there are two damper linkages instead of one and they are located behind a plastic cover. One of the plastic clips on the linkage may be broken preventing the linkage from operating the damper. When the damper fails to operate, the system fails to full heat. Most German cars are designed to fail this way. It's a safety feature to keep you from freezing in winter. The first picture below shows a linkage that has come loose from the support because the metal clip is broken. The second picture show the linkage properly in place with a new support and clip along with the part numbers for the support and clip.
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Friday, August 8th, 2008 AT 9:45 PM