Intake Manifold Temperature Switch - Not Functional
90porsche02Page 1 of 3 February 2, 1990
Subject: Temperature Switch for
Intake Cooling
Model Group
944 S2 1
Part Identifier Number
1914 9002
ATTENTION: Service Manager/Service Technician
Models Affected: 944 S2 Model Year 1990 (L)
Concern: No function of the intake manifold temperature switch for engine compartment cooling.
Cause: A bridging harness between C.E.B. plug "L" 3.2 and plug "J" 4.2 necessary for operating of the engine compartment/intake air cooling was not installed in production. (See 944 S2 intro book WKD 496 021 for description of operation.)
Vehicle Information: Vehicles between the following VIN numbers, 94-LN 450102 to 94-LN 450121 Coupe 94-LN 480102 to 94-LN 480304 Cabriolet should be checked whenever the vehicle is in the workshop for normal service or other repairs and, if necessary, a bridging harness installed.
Parts Required: Wire Connector 1.5 mm Qty. 1 PN 999 652 474 22 Wire Connector 2.5 mm Qty. 1 PN 999 652 475 22 250 mm length (approx. 10 inches) 1 mm wire (16 GA.) obtained locally.
Work Procedure: 1. Pre-assemble bridging harness as shown:
2. Drive vehicle onto hoist. Make note of radio presets and/or theft code then disconnect the battery negative cable.
Figure 1:
Figure 2:
3. Remove C.E.B. cover and loosen C.E.B. retaining screws (arrows Fig. 1). Lift C.E.B. upward to expose plug connections. Release plug connector lock (arrow Fig. 2) and pull out plug connectors "L" and "J".
Figure 3:
4. Disassemble the elements of plug "L" and remove the connector from position 3.2 (black/yellow wire) using a suitable tool (see Fig. 3). Cut off the connector and strip the wire insulation back approximately 5 mm.
Connect the stripped end of the pre-assembled bridging harness to the black/yellow wire and install connector (2.5 mm 999 652 474 22) and crimp securely. Reinstall the connector back into position 3.2 of plug "L" and reassemble the elements. Reconnect plug "L" into the C.E.B.
5. Disassemble the elements of plug "J". Connect the free end of the pre-assembled bridging harness into position 4.2. Reassemble the elements and reinstall plug "J" into the C.E.B. Engage the plug connector lock and reinstall the C.E.B. into the vehicle.
6. Re-connect the battery negative cable and switch the ignition to the radio position (X contact).
Figure 4:
7. Raise the vehicle on the hoist. From underneath the vehicle, disconnect the temperature switch under the intake manifold (arrow Fig. 4) and bridge the wires. The engine cooling fans should then run at the first speed, indicating proper operation of the circuit.
8. Re-connect the temperature sensor wires. Reset the clock, radio theft code and presets. Drive the vehicle until it reaches normal operating temperature and perform system adaptation.
Figure 5:
9. Clean cosmoline from a small area of the intake manifold and apply a black paint dot (arrow Fig. 5) to indicate service installation of the bridging harness.