Compressor Clutch Relay: Description and Operation

COMPRESSOR CUT-OFF RELAY





PURPOSE
The compressor cut-out relay (28) is used to improve engine speed stabilization after start-up and low engine speed performance by cutting out compressor depending on operating conditions.

Compressor Cut-Out Microswitch:

OPERATION
The compressor is activated via control unit (28) 10 seconds after an engine speed of 600 rpm is reached. This improves engine speed stabilization after start-up. To improve full throttle from standing-start acceleration with engine speeds below 1050 rpm, the compressor is cut-out by microswitch (31) via control unit (28). The compressor is reactivated when an engine speed of approx. 2150 rpm is reached. If the accelerator pedal is released before 2150 rpm, the microswitch opens and the compressor is reactivated immediately via the control unit. If full throttle is applied after reaching an engine speed of 1050 rpm, the compressor will not cut-out.

Initial Compressor Cut-in 10 seconds after 600 rpm
Compressor Cut-out full throttle with engine speed below 1050 rpm
Compressor Cut-in[1] 2150 rpm or if accelerator pedal is released

CONDITIONS
[1]Full throttle standing-start with engine speed below 1050 rpm

Compressor Cut-Off Relay:

LEGEND
3 = 1 Pin Plug
26 = A/C Compressor Clutch
27 = Pressure Switch for A/C Compressor
28 = Control Unit, A/C Compressor Kickdown Cut-out
31 = Microswitch, Compressor Cut-out (Initial acceleration improvement)
96 = Solenoid Valve, Automatic Transmission
97 = Kickdown Switch
a = Control Unit, EGR, Terminal 25
b = To Fuse Box (Circuit 15X)
c = To Anti-icing Switch
d = To Temperature Control Unit (Terminal 2)
M1 = Main Ground, Behind Instrument Cluster
M5 = Ground, Engine
M10 = Ground, Battery

Color Code
sw = Black
rt = Red
ge = Yellow
ws = White
bl = Blue
gn = Green
br = Brown