Window only rolls up when engine is warm?

[Kemo]

All,

i have an 81 SC with a weird issue...as of late, both of the driver side window switches only work when the engine is warm. when i first start the car it goes into a low idle (~450rpm) and slowly rises over the next two minutes to about 800 and eventually to 950 or so.

during this time the window switches on the driver side dont work for either window.

after warming up and revving the engine to about 2-3k, they start to work


any ideas???

[GH85Carrera]

First guess is a bad or weak voltage regulator or alternator. Test the voltage at the battery when it first starts, and again later when warm.

[Coastr]

I would agree. Insufficient power from your alternator. I bet headlights are dim at idle as well.

Also check ground strap and other earths

[86 911 Targa]

Jumper your car with another
battery when cold.

Then check your windows.

G.

[LIRS6]

Fix your CIS issues as well