1999 Buick Lesabre rear defrost

You need to start by checking the fuse. If it's good, then you need to check for power to the switch. Let me know what you find.

Joe

I have a feeling the switch itself is bad. What happens is they turn on, but when they are put under a load, they can't provide enough power. Regardless, move back to the window where the defroster grid plugs in. Turn the power on and see if you are getting 12 volts to the grid at the power supply. If you are not, it could be a couple problems, a break down in the wiring to the grid, or the switch itself. Make sure there is 12 volts going both in and out of the switch before moving on to the other steps. Also, make sure the swith output is connected to the wiring when checking it so we know if the switch is the problem.

Let me know what you find.