Radiator Fan Switch - Wiring Changed For Reliability: Overview

9221mitsubishi01

NO.: TSB-89-14-001

DATE: June, 1989

MODEL: Precis


SUBJECT:
MODIFICATION TO RADIATOR FAN THERMO SWITCH WIRING ON PRECIS


PURPOSE
To improve the reliability of the radiator cooling fan thermo switch, a new switch and wiring harness were installed on production vehicles starting December 5, 1988. For all Precis vehicles built before this date, a modification kit has been made available and should be installed. As a reference to this bulletin, 3 schematics of the new cooling fan wiring are supplied on adhesive backed paper. Apply one schematic to the inside back cover of the 1987, 1988, and 1989 Precis Service Manuals.

DETAILS OF CHANGE
Prior to the production change, the radiator fan was controlled directly by a thermo switch in the bottom radiator tank, which closed to ground whenever the engine coolant temperature reached a predetermined temperature. Under certain conditions, the high amperage draw during fan startup can exceed the design limits of the thermo switch. This could cause the switch to malfunction, and lead to engine overheating or battery discharge. To correct this condition on vehicles built after Dec. 5, 1988 the manufacturer has installed a new thermo switch, fan relay, and wiring harness to control fan operation. These parts are available in a kit for older vehicles and should be installed on any Precis that needs a thermo switch replaced, or has had situations of improper radiator cooling fan operation. The warranty information, parts kit, and installation instructions are described below and on the following pages.

AFFECTED VEHICLES
Precis built before December 5, 1988

WARRANTY INFORMATION
Operation code: 25360R0F

Operation description: Thermo switch assembly

Operation time: 0.3 hr.

PARTS KIT DESCRIPTION
Kit part number: 25360-21A00 Repair Kit - Thermo Switch Kit Components:
Description Quantity
Radiator Fan Motor Relay Harness 1
Joint Connector 1
Power Relay 1
Strap 2
Thermo Switch 1