Greetings JCD,

If you are concerned about no heat from your center vents, don't be. The center vents are only used when you put the temp dial to the cold setting, whether it's outside air or a/c . These aren't used when in the heating mode. Seems strange, but that's the way it's designed. If you are getting fairly warm to warmer air out of your side vents in the heating mode, that's about normal. The temp wheel can be adjusted to increase the heat a little more, but it will also affect cooling in the Summer to some extent. I'd check the interior temp sensor in the right front speaker housing to see if it's all gunked up or if the lower hose that supplies blower air to it is deteriorated.

Charles

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'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan