A 2005 Chevrolet Malibu came in with no outside turn signals working and the inside indicators
were flashing quickly. I know this sounds a little crazy but the first thing to check is codes. Codes B3948, B3949, B3950 and B3951 were stored for possible short to power. With all of these codes I was expecting to find a faulty body control computer but I decided to use old experience and realized that if the bulbs had a faulty ground then the body computer might interpret that condition as a short to power. Let’s check the basic first. I went to the right front light assembly and removed it in order to inspect the bulb wiring.
There are two 10 mm headed screws that hold the assembly in place.
After removing the two screws the light assembly can be lifted up and away from the car. Next I twisted the access cap off of the assembly.
This is what I found. A burnt socket.
And a melted bulb.
I replaced the socket assembly by cutting and splicing one wire at a time, making sure to stagger the joints. Replacement sockets are available by clicking here. Although this socket is only listed to replace the rear turn signal sockets, you can see that it also clearly fits the front application as well. If you know that it will fit other year models please leave that info in the comments below.
I heated the dual wall heat shrink tubing.
Installed the socket with a new bulb in the light assembly.
Tested the right turn signals and that light worked. One down three to go. I repeated the process for the left front light assembly and that light also started working. Now to the rear lights. I started at the left rear. First I removed the one phillips head screw.
Next I went inside the trunk and removed the cargo net retaining nut.
After moving the trim cover I could access the two plastic wing nuts that hold the light assembly in place.
After that the light just pulls out. The edge above where the phillips headed screw was had to be pulled loose from some sealer that was behind the plastic.
Next I removed the turn signal socket and found yet another burnt socket. This one only comes as a subharness assembly so I removed the old and installed the new. The subharness is currently only available at your local dealership, the part number is 15869348.
Reassembled and tested and now after replacing four faulty sockets and bulbs all of the lights were working. I cleared the coded and rechecked the system and no codes returned.
I think it is a little strange that the customer waited till all of the lights failed before bringing the car in for repair. The customer claimed that all of the turn signals stopped at the same time maybe, maybe not.
As for the cause, the front turn signal sockets also are used a daytime running lights and receive a lot of use which generates heat which causes the above problems. The rear turn signal sockets also are used as stoplights and depending on driving habits can also be used a lot. Not much you could do about the DRL but the stoplights would last much longer if the driver’s would let off of the brake pedal occasionally while stopped in lines or traffic and let the lights cool.