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In my 90 LS400 when I select vent only(No air cond.) and adjust the temp to 65* the air seems nice and cool. Or it seems to be at whatever the outside air temp. is at that point in time. This time of year in San Diego it is great as I don't need to turn on the AC.
Now in our 93 LS400 when I do the same thing(in this case there is no 65* reading it say's max cold instead) the air temp coming out of the vents is not AS cool as in my 1990. It's as if the heater is SLIGHTLY on, warming up the air to a slight degree. Mind you, it's not hot air by any means, it's just not AS cool as in my 1990.
It is a little annoying as I sometimes have to turn on the AC if I want to drive with the windows up.
If the A/C system turn off and the fan off, then you'll only have the fresh air coming from the vent. The vent temp. will be a little bit warmer than the outside temp. One more thing to look for on the 93 LS, the A/C filter behind the glove comparment. If the the A/C filter is clogged up then the fresh air will not flow properly. You can look this up in the owner manual on how to remove it.
Originally posted by VVT-i One more thing to look for on the 93 LS, the A/C filter behind the glove comparment. If the the A/C filter is clogged up then the fresh air will not flow properly. You can look this up in the owner manual on how to remove it.