Mercury 90 Service Manual

5C-28 - MID-SECTION 90-830234R3 DECEMBER 1997
Troubleshooting the Power Trim Electrical System
Refer to wiring diagram on preceding page for location of wire connections.
Problem Possible Cause Remedy
Trim Switch “UP” is inoperative,
but the Cowl Switch “UP” does
operate.
1. Open wire between Wire Connection (1) and
Trim Switch.
2. Faulty Trim Switch.
1. Check for a open connection or cut wire.
2. Replace
Cowl Switch “UP” is inoperative,
but the Trim Switch “UP” does
operate.
1. Open wire between Wire Connection (2) and
Solenoid.
2. Faulty Cowl Switch.
1. Check for a open connection or cut wire.
2. Replace
Trim Switch “UP” and Cowl
Switch “UP” are both inoperative.
1. Open wire between Wire Connection (1) and
the Up Relay.
2. Open BLK wire between ground and UP
Relay.
3. Open RED wire between Solenoid and Up
Relay.
4. Faulty Up Relay .
1. Check for an open connection.
2. Check for an open connection.
3. Check for an open connection.
4. Replace
Trim Switch “DOWN” is
inoperative, but the Cowl Switch
“DOWN” does operate.
1. Open wire between Wire Connection (3) and
Trim Switch.
2. Faulty Trim Switch.
1. Check for a open connection or cut wire.
2. Replace
Cowl Switch “DOWN” is
inoperative, but the Trim Switch
“DOWN” does operate.
1. Open wire between Wire Connection (2) and
Solenoid.
2. Faulty Cowl Switch.
1. Check for a open connection or cut wire.
2. Replace
Trim Switch “DOWN” and Cowl
Switch “DOWN” are both
inoperative.
1. Open wire between Wire Connection (3) and
the Up Relay.
2. Open BLK wire between ground and Down
Relay.
3. Open RED wire between Solenoid and Down
Relay.
4. Faulty Down Relay
1. Check for an open connection.
2. Check for an open connection.
3. Check for an open connection.
4. Replace
Trim Switch “UP” and “DOWN”
are both inoperative, but the
Cowl Switch does operate.
1. 20 AMP Fuse blown.
2. Faulty trim switch.
3. Wire is open between fuse holder and
solenoid.
4. Wire is open between fuse holder and trim
switch.
1. Replace fuse. Locate the cause of the
blown fuse. Check electrical wiring for a
shorted circuit.
2. Replace
3. Check for a open connection or cut wire.
4. Check for a loose or corroded connection.
Trim Switch and Cowl Switch are
both inoperative.
1. One of the Trim Pump Motor wires is open
between the motor and the Relays.
2. Faulty trim pump motor.
1. Check wire connections (4) for loose or
corroded condition.
2. If voltage is present at connections (4)
when the appropriate trim button is pressed,
than motor is faulty. Replace motor.
Trim system operates (motor
runs) without pressing the
switches.
1. The Trim or Cowl switch is shorted. 1. Replace

Mercury 90 Specifications

General

Brand	Mercury
Model	90
Category	Outboard Motor
Language	English