I've seen this problem for years, but i'm finally bored enough to post it (the boss is away this week).

here's the situation. . .

I'm driving up a hill in my 87 240 in, let's say, third gear. This is a fairly steep hill in a residential area, so I'm going to have to downshift soon unless i want to get out and push. Before i downshift, as the car is reaching the "bottom" of third gear and the pedal is to the floor, THE FOOT VENT COMES ON. the foot vent wasn't on before, and the switch still works that turns it on, as do the defrost and recirc switches. If i turn on the foot vents, and i repeat the above steps, nothing out of the ordinary happens (i.e. they don't do the opposite and shut off)

has anyone seen this before? is there a solution? is it cheap? if not, i'm happy just telling people that my car is possessed so that i don't have to drive them arond anymore.

Mine does this too. Thanks for the hint about the check valve. Do you think it will help restore my non-working cruise control? A vacuum hose to the cruise was replaced last fall, so I figure its vacuum related.

thanks!

I had the same problem with the floor vent. Replaced a split vacuum hose and it fixed both the floor vent thing and a cruise control problem.

The check valve Warren is reffering to is located on the engine intake

manifold. You'll be able to identify it by being the one that changes from

about 3/8" size down to a very small hose that runs into the fire wall

just behind cylinder four on the exhaust side of the engine. You should

see a check valve in the hose before it changes to the small hose.

Dave 82 242ti

Your vacuum check valve needs to be replaced. Also look for cracked or broken vacuum hoses or a disconnected one at the vacuum reservoir.

Otherwise, it's haunted.