Any information on instaclear?

[lincolnjlincoln2]

I recently got an absolute chestnut of a deal! I picked up a 1991 signature black on black on black "has the black Presidential town sedan top". I make the third owner of this rig, the previous owner bought it in 1996 and it's spent the better part of the past 20+ years in his garage only driven on nice days, all I know is this thing is cherry. The reason for the post is this car was optioned with the instaclear windshield and I have verified it to be the proper glass the problem I'm having is when I turn it on, the interior lights dim and within a second or two, it shuts off "the instaclear". I have looked both high and low for resources on how to troubleshoot this thing, but it appears that this option was'nt the hottest ticket and since heated windshields never took off in the US, there isnt a whole lot of info. any guidance would be greatly appreciated!

 

[joegr]

... the problem I'm having is when I turn it on, the interior lights dim and within a second or two, it shuts off "the instaclear". ...

My understanding (could be wrong) is that it disconnects the alternator from the 12V system and then runs the alternator at a much higher voltage to pump power into the higher resistance of the windshield. The rest of the car has to run completely on battery only while the feature is being used. If the battery is not in very good shape and/or is not the correct battery for TCs with this option, then it won't work.
I would verify that the battery is actually correct for your car with the instaclear option, and if it is do some aggressive load testing (or just replace it if it is three years old or older). Just because it is able to start the engine does not mean it is in good enough shape for this.

 

[lincolnjlincoln2]

My understanding (could be wrong) is that it disconnects the alternator from the 12V system and then runs the alternator at a much higher voltage to pump power into the higher resistance of the windshield. The rest of the car has to run completely on battery only while the feature is being used. If the battery is not in very good shape and/or is not the correct battery for TCs with this option, then it won't work.
I would verify that the battery is actually correct for your car with the instaclear option, and if it is do some aggressive load testing (or just replace it if it is three years old or older). Just because it is able to start the engine does not mean it is in good enough shape for this.

I ended up getting the factory repair manual and did some researching and while I’m not proficient, I agree you are right, it does disconnect the alternator from the rest of the car, but it’s also supposed to raise the rpm’s to compensate for the higher pull, mines not doing that, but to the point I did connect a charger up to it and it did seem to keep the light on longer. The battery is only about a year old but I just got the car. I’ll have to dig a bit deeper but I’ll update when I get this figured out.