When I set the alarm only the left side indicator lights flash, the right no light flash. the alarm work OK.

I would like to know why only one side front and back indicators lights do not flash when I arm the alarm.
Apart for that the alarm work fine, it's not a big problem but annoying.

My car has 100000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
When the alarm was installed the alarm output wire for the lights need to be tied into a parking light circuit or turn signal circuit. Whom ever installed your unit hooked the light output wire to only the left turn lights. There is not a problem and if you wanted it to be fixed it would need to be rewired.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

Triggers. When an active alarm is set off, it usually makes the horn of the vehicle sound and the lights flash until it is deactivated with the key fob or the ignition key. Some vehicles only have this feature on the driver`s door, while other systems alert if any door or the trunk is opened.
Fortunately, carmakers came up with an easy way to indicate (pun intended) if you have a problem. If the dashboard indicator light is flashing faster than usual, something isn`t right. In most cases, it`s simply that one of the bulbs has blown and needs to be replaced.
One way to test your alarm is to hit the panic button once you`ve locked your car to see if the alarm sounds. If you have an older alarm system, you might also have a red light inside the car that flashes once the alarm is set.
Car alarms rely on the electronic component of the vehicle, and disconnecting the battery should both silence the siren and reset your alarm. Open up the hood, locate the battery, and with a wrench, remove the negative terminal. Then reconnect it after a minute has passed.
Most modern cars have a dash light that indicates that the anti-theft system has been triggered. The icon for the anti-theft system looks like a car and a lock combination. When this light is on and flashing (it will be either or blue), it will indicate that your car`s anti-theft system is activated.
The Anti-theft Light in the dash of your car should flash periodically to show that the system is engaged and active. You have to lock the doors of the car (without it running) for the alarm to engage.
Indicators must flash between 60 and 120 times per minute.
The most common symptom of a bad or failing turn signal / hazard flasher is hazards or turn signal lights that do not function. If the flasher breaks or has any internal issues it can cause the lights to malfunction, or not respond at all when the turn signal lever or hazard light button are pressed.
Test your alarm system:

Go to a door that is secured by the alarm and open the door. Do this for all devices that are connected to the alarm. Tripping each device will send an alarm signal to the monitoring center. In this manner all devices are being tested to be sure they are sending a signal.

If you aren`t sure what alarm you have, you should again refer to your owner`s manual. A mechanic can also help you. Of course, if it`s just a matter of knowing if it`s a silent alarm or not, you can just give your locked car door a tug and see if an alarm is set off.
You`ll need to locate the fuse responsible for your car alarm`s power. Fuses send electricity to different parts of your car, so removing the alarm`s fuse won`t stop power from the overall battery connected to your engine (remember, car alarms need to run when the engine is off, so they have a distinct fuse).
Locate the appropriate fuse box.

Most modern vehicles have more than one fuse box located throughout the vehicle for various electronic components. Use the vehicle`s owner`s manual to identify the box with the fuse powering your factory car alarm. The fuse box may be located in the engine bay or the cabin of the car.

Theft Alerts is a premium feature with AT&T Mobile Security Plus. It provides you with the information needed to recover your Android device if it`s stolen.
Passive anti-theft systems

Passive anti-theft devices include: An alarm system that activates automatically when you turn the ignition off or shut your car door. Automatic disabling devices such as a computer chip in the ignition key. This device will prevent the car from starting if an unrecognized key is used.

PIR is an electronic sensor that detects the motion of objects, by measuring the level of IR radiation.
This blinking red light in the car is more of a built-in alarm system for your vehicle where it could prevent someone from burglarizing your vehicle. This blinking red light can be referred to as the anti-theft or immobilization light.
These are bright blue and super visible so work as a good deterrent.
Flashing can request or insist that a leading driver speed up or change lanes to get out of the way of a faster following driver. Headlight flashing may constitute aggressive driving, and can be used in an attempt to intimidate others into speeding or otherwise driving unsafely.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

When I set the alarm only the left side indicator lights flash, the right no light flash. the alarm work OK.
ANSWER : When the alarm was installed the alarm output wire for the lights need to be tied into a parking light circuit or turn signal circuit. Whom ever installed your unit hooked the light output wire to only the left turn lights. There is not a problem and if you wanted it to be fixed it would need to be rewired.

Okay so when I turn my lights on at night my brake lights do not work, when I don’t have my lights on they work fine.
ANSWER : Hi there. Based on your inquiry, it’s highly probable that you have a damaged light switch or some electrical fault inside the turn signal relay. However, it’s also possible that the brake switch above the brake pedal could also be the source of your problem. Due to the fact that multiple electrical components might be causing this issue, it’s a smart idea to first have a professional mobile mechanic complete a brake lights are not working inspection, so they can determine what’s causing all of these issues and recommend the right repairs.

No dash lights, back right tail light is out, no parking lights. Brake lights work though as does head lights.
ANSWER : Hi there. In many cases, when you have electrical problems like you’re describing, it’s caused by multiple electrical component failure. It’s likely that a few electrical relays are not working; especially if you have systems that utilize the same components (such as your brake light and tail lights). I would recommend having a professional mobile mechanic come to your location to complete an electrical problems inspection first, so they can pinpoint what is damaged and recommend the right repairs.

All dashboard lights and tail lights do not work after driving through a lot of snow. Headlights work. And brake lights work.
ANSWER : Hello. We’ll be happy to help you. There are a few things that I recommend checking to discover why your lighting system is malfunctioning. The headlight dimmer switch should be checked. Along with the wiring harness above the right front tire behind the fender well cover. Also
the main fuse under the hood should be inspected because other people with your particular vehicle have had similar lighting issues if that fuse goes bad. It will be a great idea to check the rest of the fuses in that area too while checking the main fuse. Once the fuses are checked inside of the main fuse box then I would check the fuses inside of their interior fuse box. The interior fuse box should be located on the driver side of the dashboard near where your legs would be. If you need more assistance with repairing your vehicle please keep in mind that our organization provides Mobile Mechanics who can help you diagnose and repair your vehicle, all at competitive rates.

My turn signals on my right side don’t work at all and the indicator blinks fast like a bulb is out. What could it be?
ANSWER : Have you tried replacing the bulbs on the inoperative side already? It could be the bulbs are out or if the turn signal lighting on that side has a separate ground, there could be a fault there. Consider hiring an experienced technician like one from YourMechanic who can come out and take a closer look with access to the system wiring diagram in order to offer a more personal diagnosis. The technician can install a new bulb and check for power and start there.

Electrical problems after upgrades
ANSWER : Hi there. From the description you have provided, all of your vehicle’s electrical problems began with the "upgrades". Unfortunately this could be a can of worms to repair. Assuming, you had a qualified technician install the vehicle’s radio and lighting upgrades and all was fine after the installations. This would lead me to believe your vehicle has several problems. The first place to look would be fuse(s) for the inoperative components. Next, to look for shorts to power the components staying on. If you can find the problem yourself, I recommend having your vehicle’s electrical problems diagnosed and repaired by a certified technician, like one from YourMechanic.

Dash, Tail/brake, dome, trunk, glovebox, and door lights won’t work, dash doing weird things.
ANSWER : Hi there. Sure would appear a lot is going on electrically all at once. This could be, a problem in the PDC (power distribution center). The PDC is typically located under the hood and contains numerous fuses and relays. I don’t believe any one fuse will resolve all of the electrical issues. There is a possibility, it is not a power supply issue. It may be, the result of a poor electrical ground common to the inoperative components. Proper circuit testing should be performed. This would confirm the cause of multiple electrical failures. I recommend having your vehicle’s electrical problems be diagnosed and repaired by a certified technician, such as one from YourMechanic.

Passenger side brake light is not working – 1971 Volkswagen Super Beetle
ANSWER : It may just be chance that the other light quit working as well. Replace ALL of the brake light bulbs at the same time with the right bulbs and if they still do not work, suspect a problem in the circuit. Have a trained professional inspect the vehicle’s brake lighting circuit for any faults like a blown fuses or a malfunctioning switch. A certified technician from YourMechanic can come to your car’s location to inspect the brake lights and perform appropriate repairs.