87 SDL - 2 pressure sensors on AC drier?

[sixto]

The CD manual doesn't have an AC diagram specifically for the 87 SDL. There are diagrams for the 86 SDL and 87 gassers. None of those diagrams show that there are two pressure sensors on the 87 SDL drier. My car was converted to R134a before I got it. There is one sensor with bu/rd wires as in the diagrams and a second sensor with brown wires that tuck into the harness. If it's an add on, it's a very clean and factory looking job. Any idea what this sensor is for?

Sixto
91 300SE
87 300SDL
83 300SD

If this is a US model it is not add on air. Since you know where these sensors are, you should be able to trace the wires using an ohmmeter point to point. Put one lead on the disconnected clutch wire, then probe to the low pressure switch (or whichever switch it leads to next)and learn which one leads there. Then put the ohmmeter lead on the other switch wire and probe with the other meter lead to find where it goes.

It's always about ten times easier with proper schematics, but I've found that if the schematics are close but not accurate they can cause more frustration than good.

Best of luck,

[jerryb]

There are 2 sensors, if I remember right 1 for temp and 1 for pres.
Jerryb

[ILUVMILS]

The large round switch with the connectors pointing "up" is for low pressure cut-out. The other switch ( usually red with short wires ) is the high pressure switch to activate the auxiliary fan.

[Arthur Dalton]

The Quickie Test to tell which sensor is what is , w/key on, jumper the sw.
The high pressure one will kick on the aux fan.