Pontiac Fiero 1988 Service Manual page 1130

INTERIOR LIGHTS DIMMING
A: INTERIOR LIGHTS DIMMING T E S T
(TABLE 3)
Connect: A T E S T LAMP
At: REMOTE DIMMER CONNECTOR
(Connected)
Conditions:
• Light Switch: PARK
> Dimming Control: BRIGHT
Connect
Between
Correct
Result
For
Diagnosis
D (BRN)
& Ground
Test Lamp
lights
See 1
B (DK GRN/
WHT) & Ground
Test Lamp
lights
See 2
C (DK GRN)
& Ground
Test Lamp
lights
See 3
® Slowly adjust dimming control to DIM
C (DK GRN)
& Ground
Test Lamp
dims
See 3
• If all the results are correct, check the
DK GRN (44) wire for an open (see
schematic).
1. Check BRN (9) wire for an open (see sche-
matic)
2. Check DK GRN/WHT (944) wire for
an open
(see schematic).
3. Replace Remote Dimmer.
CIRCUIT OPERATION
Battery voltage is applied at all times
through the TAIL Fuse to the Light Switch.
When the Light Switch is in PARK or HEAD,
battery voltage is applied to the dimming con-
trol in the Panel-Interior Lights Control and to
the Remote Dimmer. Adjusting the dinuning
control changes the voltage applied to terminal
B of the Remote Dimmer. As the voltage at
terminal B increases, the Remote Dimmer
increases the current flow to the bulbs and the
bulbs become brighter. As the voltage at termi-
nal B decreases, the Remote Dimmer decreases
the current flow to the bulbs and the bulbs get
dimmer.