I’ve owned my 84 LX convertible for about 30 years, and in that time I’ve repaired or replaced about everything on it, but it has me stumped now. The temperature control slide on the HVAC panel causes the fan to cut in and out as it is raised from cool to warm. Also, the mode selector causes the fan to stop as it is raised through the different selections. Works fine in the A/C positions (as long as the temperature slide is on cool), but the fan stops when I get to the heat and defrost settings. Sometimes the I can get the fan to run on vent if I wiggle the temperature control slide. I’ve removed the assembly and cleaned contacts, and I found some broken plastic which I repaired. I assume there are some electrical contacts along the slide surface, but I really don’t understand how it works. Is anyone familiar with this unit?

Well, no one offered any input so I had to figure it out on my own. It turns out that 35 year old plastic gets pretty brittle and has a tendency to crack. Who would have thought. I took it all apart again and found some additional cracks, which had allowed the slide contacts to get out of position. After putting everything back where it is supposed to be and repairing the cracks, it works fine. It’s a good thing too. I found one used assembly that the guy was asking $300 for. It was probably 35 years old too.