* Faulty or loose ground connection: The turn signal circuit uses a ground to complete the circuit. A poor ground connection can cause a voltage drop that affects other systems, including the engine control module (ECM). When the added load of the turn signals is introduced, the already weak ground might become insufficient, causing the engine to shut down. This is a common cause of intermittent electrical problems in older cars.
* Problem with the alternator: The alternator might be failing and not producing enough power. The additional load of the turn signals pushes the alternator beyond its capacity, causing a voltage drop leading to engine shutdown.
* Wiring issue: A short circuit or damaged wiring in the turn signal circuit could be drawing excessive current, causing a voltage drop affecting the ECM or another crucial engine component. This could also be a corroded connector.
* Faulty ignition switch: While less likely, a failing ignition switch could be intermittently failing under the added load of the turn signals.
* ECM problem: In rare cases, a malfunctioning ECM might misinterpret the load from the turn signals and shut down the engine as a safety precaution. This is less probable given the other more likely causes.
* Low battery voltage: Although less likely if the engine is running, a low battery could exacerbate other issues leading to engine shutdown when adding the load of the signals.
What to do:
It's extremely dangerous to drive a car with this problem. You should have it towed to a mechanic immediately. Don't try to troubleshoot this yourself unless you have significant automotive electrical experience. Attempting to diagnose and fix this yourself risks further damage or injury.
The mechanic will need to:
* Check the battery and alternator: This is the first step in any electrical diagnosis.
* Inspect all wiring related to the turn signals and the engine control system: Look for loose connections, corrosion, and breaks in the wiring.
* Check grounds: Thorough ground connection checks are critical.
* Diagnose the ECM: In rare cases, it might need attention.
In short, don't drive the car until it's fixed. The underlying cause is likely a serious electrical fault that requires professional attention.
