Ruling on hanging Soorat al-Ikhlaas on the rear window of the car as a reminder

There is nothing wrong with hanging Qur’aanic verses for the
purpose of reminding and exhorting, so long as they are put in places that
are appropriate, such as the walls of meeting places and offices, in such a
way that the verses will not be exposed to disrespectful treatment. 

In the case of hanging verses in car windows, there is the
fear that they may be exposed to disrespectful treatment and damage, so it
is better not to do that and to be content with some adhkaar or advice. 

Shaykh Ibn Baaz (may Allah have mercy on him) was asked:
There are some who say that hanging soorahs or verses of Qur’aan on the wall
is haraam. Please note that these verses or soorahs are only hung up because
of their virtues, such as Soorah Ya-Seen or Ayat al-Kursiy and so on. We
hope that you can explain the ruling on that; may Allah reward you with
good. 

He replied: There is nothing wrong with hanging verses and
soorahs on the wall in offices and meeting places for the purpose of
providing and exhorting, according to the correct view. Some contemporary
scholars and others regarded it as makrooh, but there is nothing wrong with
that if it is done for the purpose of reminding and exhorting, and it is in
an appropriate place such as a meeting place or office and the like. (There
is also nothing wrong with) hanging a hadeeth of the Prophet (blessings and
peace of Allah be upon him). All of that is exhortations and reminders. But
if the aim behind it is something other than that, such as believing that
they offer protection from the jinn or the evil eye and so on, it is not
permissible to do this with that intention and that belief, because this is
not narrated in sharee‘ah and there is no basis for it. And Allah is the
source of strength.

End quote from Fataawa Islamiyyah. 

But if the purpose of hanging it is to translate the meaning
of this soorah or other verses and soorahs of the Qur’aan, then the issue of
hanging it is less strict with regard to translations because they do not
have the same sanctity as the Qur’aan and do not come under the same
rulings. 

And Allah knows best.