2005 Buick LeSabre backup lights don't work

Backup lights don’t work. Bulbs are ok.

Backup light signal is broken or the ground wire from the backup lights has corroded away. A voltmeter and ohmmeter will tell you the answer. Pull the backup light bulb, probe the 2 contacts with an ohmmeter with the other probe on a good ground. If one of the 2 gives you a good ground then get a helper. Have the helper start the car, shift into reverse while firmly holding the brake. Probe the contact that ISN’T the ground with a voltmeter. Do you have about 12 volts or so? No? Then a little more digging is in order.

I don’t see a simple backup light switch listed on Rockauto which leads me to think the transmission range selector switch for the shifter may have failed.

I don’t see any volts at the connector in the trunk. I haven’t ohmed out the bulbs , but on the trans. selector bracket there 3 switches but I don’t know which one might be for the B U lights.

Thanks for your reply and Info…


Found broken Black/Grnd. wire in Bundle. Was short so stretched and broke with opening of trunk.

Thanks for the helpful info.


P.S. Not much corrosion here in Las Vegas…