Lighting Gremlins - F-Body Road Racing and Autocross Forums

The Pontiac didn't pass State inspection - right front turn signal wasn't operational. How hard can this be? I replaced the bulb while the tech continued the inspection. Still didn't work. Off to home I go....

I pulled the socket out and tested for 12V. Nothing in the socket, nothing in the wire leading to the socket. (BTW, 12V for the side marker light was present, just not for the turn indicator).

Send in the Gremlins. My wife noticed the left headlight was dim. So tonight I started playing with lights while I sat behind a Van at a stoplight.

Turn headlights on, low beam, both lights look normal. Turn on highbeams - right side headlight acts normal (high beam on), left side goes dim (lets call it half the brightness). Turn off highbeams, right side again acts normal (low beam on), left side looks the same as when the high beams were on (the same half-brightness). Turn on high beams, right side goes to high beam, no change and half-brightness on the left.

Turn the head lights off completely, then back on. Low beams on both sides look normal. Turn on high beams and the same right-side-works-left-side-half-brightness thing happens. Turn head lights off, then on - low beams normal, turn on high beams.......

I'm still behind the Van, the right front turn signal is WORKING!!! (IMG:http://www.frrax.com/rrforum/style_emoticons/default/banghead.gif) and the left side blinks slowly, at about half the rate of the right side, and has a slight delay before the blinking begins. On the drive home, the left side turn signals quit working all together (judging by the reaction of the car following me and the dash signal light staying solidly lit).

At first I was thinking Turn Signal Switch, but now I'm not so sure. It's been too long and many brain cells lost to senility since I had to really read a schematic. Any suggetions on where to begin troubleshooting? Looks like all the lighting is directed through the DRL module, should I be suspecting it is going bad? Maybe the turn signal switch? I'm thinking Module, or even relay, since the headlight trouble seems to reset once power is removed, but would a relay explain the intermittant turn signals? (IMG:http://www.frrax.com/rrforum/style_emoticons/default/huh.gif)

Jeff97FST/A View Member Profile	Dec 21 2006, 01:04 AM Post #1
Mr. 3rd Place Group: Advanced Members Posts: 537 Joined: 24-December 03 From: Rindge, NH Member No.: 32	The Pontiac didn't pass State inspection - right front turn signal wasn't operational. How hard can this be? I replaced the bulb while the tech continued the inspection. Still didn't work. Off to home I go.... I pulled the socket out and tested for 12V. Nothing in the socket, nothing in the wire leading to the socket. (BTW, 12V for the side marker light was present, just not for the turn indicator). Send in the Gremlins. My wife noticed the left headlight was dim. So tonight I started playing with lights while I sat behind a Van at a stoplight. Turn headlights on, low beam, both lights look normal. Turn on highbeams - right side headlight acts normal (high beam on), left side goes dim (lets call it half the brightness). Turn off highbeams, right side again acts normal (low beam on), left side looks the same as when the high beams were on (the same half-brightness). Turn on high beams, right side goes to high beam, no change and half-brightness on the left. Turn the head lights off completely, then back on. Low beams on both sides look normal. Turn on high beams and the same right-side-works-left-side-half-brightness thing happens. Turn head lights off, then on - low beams normal, turn on high beams....... I'm still behind the Van, the right front turn signal is WORKING!!! (IMG:http://www.frrax.com/rrforum/style_emoticons/default/banghead.gif) and the left side blinks slowly, at about half the rate of the right side, and has a slight delay before the blinking begins. On the drive home, the left side turn signals quit working all together (judging by the reaction of the car following me and the dash signal light staying solidly lit). At first I was thinking Turn Signal Switch, but now I'm not so sure. It's been too long and many brain cells lost to senility since I had to really read a schematic. Any suggetions on where to begin troubleshooting? Looks like all the lighting is directed through the DRL module, should I be suspecting it is going bad? Maybe the turn signal switch? I'm thinking Module, or even relay, since the headlight trouble seems to reset once power is removed, but would a relay explain the intermittant turn signals? (IMG:http://www.frrax.com/rrforum/style_emoticons/default/huh.gif)

Marty View Member Profile	Dec 23 2006, 10:14 PM Post #2
Member Group: Advanced Members Posts: 71 Joined: 27-June 05 Member No.: 787	Check to see if you have the same electrical problems with the brakes firmly pressed as you do without them pressed. I had something similar and it turned out the wiring harness passes behind the brake booster. The pressure of the break boosters flexes the fire wall just enough over time to short the wires.