Rear defroster turns off too soon

[Woosch]

We got our first real blast of cold air in Denver yesterday. Our high isn't supposed to get above freezing for a week. Driving to work this morning reminded me of a problem with my Bonneville. The rear defroster works fine, but it doesn't stay on long enough to defrost the window. The first time I turn on the defroster, it stays on for maybe 7 minutes before turning itself off. After this, if I turn it on again, the defroster only stays on for a minute or two. Is there something that needs to be replaced? What tells the defroster to turn itself off? Thanks in advance!

[95se]

IIRC it should stay on for 10 mins before it turns off. Im not sure though

[Jfridge92]

Mine in the LeSabre stays on for about 7-10 minutes, never really timed it though. That sounds about normal, you just have to turn it back on if it's not done yet.

[95se]

In my case its for heavy frost so it always gets turned back on lol

[nos4blood70]

Mine stays on for about 15 minutes... But it's also the 2000+.

[RJolly87]

Same here, it's a some thermo electric switch that shuts it off I think.

[Zeik75]

my 88 stays on for 15 min, I thought that there is a timer in the switch though, the 2000 is something similar but I don't think it is a timer.

Do all the strips work or is there a line of ice still on the window? you could have a broken strip of lose end connections that could be doing something funky when it gets hot, worth checking anyway and you should be able to check easily enough.

[Woosch]

Do all the strips work or is there a line of ice still on the window?

All the strips work, and the defroster does a good job. It just turns off too soon. I wonder if the thermal switch is available.

[TUFFBONNEVILLE]

i turn my on and the car shuts off so i dont use it anymore lol