إما أن تصلح المصابيح الخلفية أو إشارات الانعطاف.

It is the Arabic pattern for either ... or.

So the sentence is setting up two alternatives:

• إما = either
• أو = or

A very common variant is إمّا ... وإمّا ..., where إمّا is repeated before the second option too. In normal unvowelled writing, the shadda in إمّا is often not shown, so you may see إما.

Here أن introduces a verb clause after إما.

With an imperfect verb, أن normally puts that verb into the subjunctive form. In fully vowelled Arabic, that affects the ending of the verb, but in ordinary writing the short vowels are usually omitted, so you often cannot see the change.

So after أن, the verb is understood as something like:

• تُصلِحَ if the meaning is repair/fix
• تَصلُحَ if the meaning is be okay / work / be suitable

Because Arabic usually leaves out short vowels, تصلح can represent more than one verb form.

Two likely readings are:

• تُصلِحَ from أصلح = to repair, fix
• تَصلُحَ from صلح = to be sound, suitable, okay, working

So the same written form تصلح can point to different meanings. The translation or context tells you which reading is intended.

That depends on which reading of تصلح is intended.

If the verb is تُصلِحَ = repair/fix, then:

• the subject is hidden inside the verb, usually you or she
• المصابيح الخلفية is the direct object

If the verb is تَصلُحَ = be okay / work, then:

• المصابيح الخلفية is the subject of the verb

So this sentence is a good example of how unvowelled Arabic can be structurally ambiguous until context makes it clear.

Two important grammar points are happening here.

1. Adjectives follow the noun in Arabic.
   So Arabic says literally something like the lamps the-rear.

2. Non-human plurals in Modern Standard Arabic usually take feminine singular agreement.

Since المصابيح is a non-human plural, the adjective appears as feminine singular:

• المصابيح الخلفية

Noticing this rule is very useful, because you will see it all the time in MSA.

It is an iḍāfa construction, often translated as a noun + of + noun structure.

Literally, it is:

• إشارات = signals
• الانعطاف = the turning / the turn

So the phrase means something like signals of turning, i.e. turn signals.

In an iḍāfa:

• the first noun is the mudāf
• the second noun is the mudāf ilayh
• the first noun does not take ال
• the second noun is in the genitive

So الانعطاف is genitive because it is the second part of the iḍāfa.

Because Arabic often omits repeated words when the meaning is already clear.

Instead of repeating the same verb again, Arabic can leave it understood from the first half.

So the longer, more explicit versions could be:

• إمّا أن تُصلِحَ المصابيحَ الخلفيةَ أو أن تُصلِحَ إشاراتَ الانعطافِ
• إمّا أن تَصلُحَ المصابيحُ الخلفيةُ أو أن تَصلُحَ إشاراتُ الانعطافِ

But the shorter sentence is perfectly natural when the repeated material is obvious.

That depends on the intended meaning.

If the meaning is repair/fix, one fully vowelled reading would be:

• إمّا أن تُصلِحَ المصابيحَ الخلفيّةَ أو إشاراتَ الانعطافِ

If the meaning is be okay / work, one fully vowelled reading would be:

• إمّا أن تَصلُحَ المصابيحُ الخلفيّةُ أو إشاراتُ الانعطافِ

Notice what changes:

• the internal vowels of تصلح
• the case of المصابيح and إشارات
  • accusative if they are objects
  • nominative if they are subjects

In normal everyday Arabic writing, those short vowels and case endings are usually omitted, which is why both readings can look identical on the page.