how to know if deforst works

pierrot · 03-23-2016, 05:22 PM

Hello,i want to know if tou could help me on knowing if my 82 sc defoster works the simple way,with out any complication like how to fog the window rear shield?i am right now at a place outdoors 80 farenheit?
is there a trixk to fog the car and then put the defrost to see if it works?
thanks

universeman · universeman's Garage

You'd need a big cooler or garage with strong strong a/c, that you could drive the car into, probably.

Another approach would to buy two cans of compressed air and spray them simultaneously (one in each hand) on the back glass, moving them around, until they're empty. That would cool the window down and probably cause fogging. Careful you don't crack the window though, need to be careful about cooling down too much in one spot. I prefer the first method.

DeRRis · DeRRis's Garage

Put a large cup of steaming hot water on your parcel shelf. This will cause condensation on the glas. It doesn't matter that it's on the inside. Turn on your defroster and you should see if your lines heat up.

universeman · universeman's Garage

^^^^^ better idea

Tremelune · 03-24-2016, 01:14 PM

If there is air blowing on the windshield, your defrosters work.

pierrot · 03-24-2016, 01:51 PM

i meant back defroster!

Tremelune · 03-24-2016, 01:53 PM

Oops, poor reading on my part. Options include checking voltage where the windshield connects, and putting your finger over each wire to see if they're warm...or you could wait until it rains of course...

Discseven · Discseven's Garage

Quote:

Originally Posted by pierrot

Hello,i want to know if tou could help me on knowing if my 82 sc defoster works the simple way,with out any complication like how to fog the window rear shield?i am right now at a place outdoors 80 farenheit?
is there a trixk to fog the car and then put the defrost to see if it works?
thanks

P... have heard that rear window defrost can be felt by hand. Might need to be cooler ambient than 80f though.

jlex · jlex's Garage

Use a digital infra-red thermometer & see if the temp rises. If it's too warm, it may not kick on if these have a thermostat (don't know if they do). Measure in AM when it's cool.
In my '70 VW bug, the grid is bad and won't heat even though you can measure volts at the window connectors. The copper making up the grids oxidizes over time and will no longer transmit voltage. Don't know if the Porsche grids are more robust.... haven't ever turned mine on.