I have a 1987 300D Turbo and my air conditioner works great for about an hour and then switches to heat and I mean hot. It stays in the heat mode until I simply turn the unit off and turn it back on and it immediately goes back to cooling for about another hour. Any ideas? The heat comes from the a/c vents.

Hi

If you check some earlier postings from me, you will see that I have some similar issues with an 83 300sd. In order of probability I was told to check

- monovalve for correct operation
- climate control unit (push button unit in dash)
- climate control amp under passenger footwell

I do not know if the climate system is identical in the 123 chassis as the 300sd is a 126 chassis, but there are lots of postings to search here...