Rick's Free Auto Repair Advice

Car dies when turn signals are used

My Car dies when I use my turn signals

Buick Regal or Century

This is a strange one at first glance. The problem takes place when you use the turn signals. It kills the engine. Or, the ABS or other dash lights come on. These vehicles are known for bad ignition switches. The power to the turn signals flows from the ignition switch to the turn signal/cornering lamps fuse located in the fuse panel on the right side of the dash.

With the key in the RUN position, test the fuse for battery voltage with the engine running. It should read 13 to 14 volts. If it does not read that high, REPLACE the ignition switch. You have a poor connection inside the switch. If the voltage checks out ok, you’ll have to check the ground wires. Start by cleaning the battery terminals and the ground cables at the radiator support/fender, engine, and firewall. If that still doesn’t solve the problem, clean the ground wire to the fuel pump. The fuel pump ground wire is BLACK and terminates at the right side of the rear shelf.

Just a warning not to jump to conclusions and start replacing the turn signal switch or the body control module (BCM). The poor connection in the ignition switch or a poor ground can scramble the electrical and kill the engine. All the symptoms will make you think it’s the BCM, turn signal switch, or an instrument cluster (the warning lights). But do these tests first. The ignition switch is the most common cause. Bad fuel pump ground comes in at #2.

© 2012 Rick Muscoplat

Posted on by Rick Muscoplat


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