Tech Tips (by ALLDATA): Sunfire’s exterior lights dim / wipers slow

2005 Pontiac Sunfire Frontside Posuncpe051 505x375TECH TIPS (courtesy of ALLDATA)

Vehicle: 2005 Pontiac Sunfire, L4-2.2L, VIN F, Automatic Transaxle

Mileage: 162,692

Problem: The owner brought his Sunfire to the shop because the exterior lights were dim, and the windshield wipers ran slow, even when the high-speed setting was selected.


Details: The first thing the technician did was to check the charging system. The alternator output was 14 volts with loads, such as lights, wipers and defrosters operating. Next, he connected a scan tool to check the body control module’s (BCM) charging system parameter identification data (PID). It was reading only 11.5 volts with the same loads on. The next step was to call ALLDATA Tech-Assist for some advice.

After reviewing the wiring diagrams, the Tech-Assist consultant found that ground point (G102) is used for the exterior lighting, the wiper motor and the BCM. The consultant suggested that the technician inspect the ground splice at that location.

Upon inspection, the technician found that G102 was corroded and the battery tray bracket it attached to was rusty and cracked. The technician performed a voltage-drop test from the negative battery cable to G102. There was a 2 volt drop.

Confirmed Repair: The technician repaired the bracket and the ground connection. After the repairs, there was no significant voltage drop, the lights were bright, and the wipers moved at the correct speeds. Fixed!