Blower Switch Problem

[sblake01]

I actually replaced the whole control assembly since one of the plastic levers was broken at the end where a cable attaches. I wasn't too difficult a fix. I examined the old one to see how it works but then tossed it out. Had I thought that anyone could use the parts, I would have kept it. As I recall, it's just a matter of lining it up to where you get all three or four positions for the fan speeds + the off position. I say three or four because IIRC the non ac cars had a three speed fan and the ac cars had a four speed fan.

[TomoHawk]

Yeah, what do I care about 4 speeds? My car was a/c equipped, but not any more, and the 3 speeds seems to be adequate. Except for those strange days when you need the windscreen defrosted/defogged NOW, so any speed is too slow.

I would like another 2 or 3 weeks to be really prepared for show season tho.

[bpilati]

If the switch on a 280 is anything like on a 240 it's just a rotary switch. I spent the last couple of days getting my blower fan working again and I ended up removing everything from the switch to the harness to the blower itself to figure out why it wasn't working. It turned out to just be a loose connector in the harness. What was interesting to me was the way that the 3 speeds actually work. There's a couple of open coils of wire that provide extra resistance for the two lower speeds. These coils are inside the blower housing and completely exposed to the airflow itself. I suppose they get warm from the current flow so having them in the airflow would cool them back down. This amounts to having a tiny heater when not running full speed. The bundle of wires that come from the switch simply determine which, if either, resistor is used.

I discovered it's the relay. There's a soldered contact in there that melts causing a loose connection, and intermittent operation. I took it apart, drilled out the soldered rivet and replaced it with a brass screw and nut. No more blower problems. :devious: