The heat and AC both began to fail intermittently about a year ago. Sometimes they would work and sometimes not.
Many of these intermittent failures could be bad solder joints inside the pushbutton unit. However, could your symptoms be explained away by a coolant flow valve (known as the monovalve) becoming incontinent? If 'AC fail' is because it starts blowing heat, and 'heat fail' is because it doesn't, both can be blamed on this one valve losing the ability to be properly controlled. In that case it's an easy and relatively inexpensive DIY repair, assuming that this _is_ a late 126 car we're talking about. Bad solder joints inside the PB array is less of a DIY repair, largely because in these there are so many contacts inside. (I've worked on two of them [or was it three?] for other people. Ugh.) Replacements are so expensive, however, that if you are a _good_ solderer it may be worth a shot. If you have to go out and buy an iron first, don't even think about it! I have a day job again, so I'm out of that biz. -- Jim
