Thread: Turn signal problem

2003 Pontiac Grand Prix SE 3.1L. 100% stock - standard bulb, no LEDs.

No right front turn signal (marker light and parking light/turn signal light not flashing), green arrow on dash not flashing, right rear light is hyper flashing.

Similarly, when the hazard light button is on, three corners of the car flash but not the the right green arrow on dash or the right front lights.

All bulbs have been tested and work. Also, the right hand marker light and parking light do illuminate when the headlight switch is put in the parking light or headlight position.

My first thought was that the problem might be caused by the right hand green arrow bulb in the instrument cluster being burned out. I checked that bulb and it was good but I installed a new one for good measure. After installing the new bulb, I still have the above described problem.

What do you think is causing the problem: turn signal flasher, turn signal relay, turn signal switch in steering column, or BCM? If it is being caused by a bad ground, I would not think that the bulbs would work when the headlight switch is turned on.

This is my first post on the forum. Thank you for your help.

Erik in Minneapolis

After mulling it over my suspicion is that it is the amber combination parking and turn signal light.

The amber light has two filaments and four contacts - one filament is the parking light and and one filament is the turn signal.

The socket has three leads so the two circuits share a common ground (blue wire "A", brown wire "B" and black wire "G" most likely ground.)

Since it does light in "parking" mode the ground is good. Tomorrow I'll take my multi-tester and for voltage to determine which wire, A or B is on the turn signal circuit and possibly the culprit.

As far as I can tell, the socket itself appears to be okay - the contacts are intact and the wires are tight.

Just an update. Problem cured (for now).

Started experiencing the same problem with the left front turn signal although it was intermittent.

Took the covers off the steering column. I wiggled and put pressure on the multifunction switch and on the connectors to make sure everything was seated properly and was able to get the left signal to work again. I continued doing this until the right signal started working. This cured the problem. However, I don't know if if this is a permanent fix. It's possible that there is a loose connection inside of the switch or the turn signal switch may be worn out.

Who knows how any of this would become loose? I suppose it's possible that when the tilt mechanism is used the wiring harness moves and if the harness doesn't move freely, the tension can pull on the connectors and the switch. I also suppose that moving the turn signal lever during the normal course of driving can also cause the switch to eventually become loose, although I am gentle with mine.

If the problem shows up again, I will replace the multifunction switch.

Connections shouldn't become loose if wiring remains stationary. The only reason a connection should become loose is if there is some movement in the wiring, even ever so slight.

Below is a photo of my steering column taken a few years ago when I removed and cleaned the ignition switch - you can see the multifunction switch wiring harness (the wiring with the two ninety degree bends by the black tape). Also attached is a stock photo from the internet.

When the steering column is tilted up or down, both the multifunction switch wiring harness and the ignition switch wiring harness will need to bend or flex further down the line where the column pivots. When the column is tilted down or up, there is probably slight fore and aft movement of the wiring harness. Over time, this may be enough to loosen the connection. (I also thought that maybe the rubber shroud on the dashboard trim may be hitting the wires or the connector but this does not seem to be the case when the steering column covers are installed.)

I doubt if there is corrosion - this is a low mileage car that spends most of its time in a nice, dry garage.

Anyway, done for now….