Subject: OK, I've verified that the circled area IS the evaporator temperature switch Author: davidc (moderator) : member since December, 2003 : 10448 posts Posted on: 2004-08-27 20:07:46

The evaporator temperature switch being removed from the evaporator. It sits between the two fan cages under the blower cowling. Its the rod at the bottom of the photo above with a black rubber elbow attached to it.


The evaporator temp switch after removal. It just plugs directly into the evaporator housing and is pressure-fitted with a rubber grommet -- no screws or bolts. The black block between my wife's hands it the compressor relay, which normally attaches to the inner side of the driver's-side of the blower cage.

For testing the temp switch, I unplugged the connector on the left and inserted a wire into the two holes to complete the circuit. The temperature switch is normally closed when the temp within the evaporator is above 32F (0C). It opens, breaking the circuit, when the temp dips below 32F, thus preventing ice from forming.

Incidentally, my evaporator temperature switch seems to be functioning fine, as is the compressor relay, so the problem must lie beyond it at the hi/lo pressure switches or the compressor itself.

David Cecil
'97 740iL, 126k miles
'86 735i, 95k miles

www.e38.org has links for everything about your BMW 7-series automobile

• Where is the evaporator temp switch in an '86 735i? - davidc 2004-08-26 20:29:41 (417 views)
  • another thing to check - dave88te 2004-08-27 10:22:48 (334 views)
  • The Evap Temp Sensor is under the cowl> - kff 2004-08-26 21:24:57 (408 views)
    • Is it the circled area in this photo? (pic) - davidc 2004-08-26 22:36:55 (547 views)
      • OK, I've verified that the circled area IS the evaporator temperature switch (pic) - davidc 2004-08-27 20:07:46 (2752 views)
        • Re: OK, I've verified that the circled area IS the evaporator temperature switch - dave88te 2004-08-27 21:26:32 (314 views)
      • Is that from the engine compartment or the passenger comp? - kff 2004-08-26 23:31:52 (348 views)
        • Here's a blowup of that area. I don't see anything that looks like (pic) - davidc 2004-08-26 23:42:59 (491 views)
          • The evap temp sw has a Gray and a Green/Brown wire to it. - kff 2004-08-27 00:08:39 (359 views)
        • You see that big metal edge on the heater box in the photo? - davidc 2004-08-26 23:36:00 (443 views)