2007 Dodge Dakota BRAKE LIGHTS FLASH

FINK88

MEMBER
2007 DODGE DAKOTA
6 CYL
2WD
AUTOMATIC
81,000 MILES

I recently made a cross country trip from NY to AZ I made it almost all of the way when I was about 150 miles from my dest I decided to stop and take a break for a few after having a smoke and jumpin back in to go my truck wouldnt start I had no battery power I wasnt overheating everyhting seemed fine afterb getting a jumpstart it was ok it made it the rest of the way no check engine lights no batt. Lights. So the next day I went to start it and nothing I charged the battery just to see if I could diagnose the problem and now that its is started again my brake lghts are flashing without any pressure on the pedal. Ould this be a bad relay? Is this a battery problem im chaniging it today? Im toatally lost on this any help would be much appreciated thanks

1 Reply

CARADIODOC

MECHANIC
33,870 POSTS

Without punctuation in there that long sentence can be read three different ways, but I think what you're seeing is a battery problem. Before you buy a new one though, double check that the charging system is working. Use an inexpensive digital voltmeter to measure the battery voltage both before the engine is started and when it's running. If you have to jump-start it, measure the voltage after the jumper cables are removed so you're not measuring the voltage from the assist vehicle.

Before the engine is started, the battery voltage should be near 12.6 volts. If it is closer to 12.0 volts, it is okay but discharged. If it is around 11.0 volts or less, it has a bad cell. Low voltage can trick the computers into thinking it's in theft mode and may be the cause of the flashing lights.

When the engine is running, the battery voltage must be between 13.75 and 14.75 volts. If it stays around 12.0 to 12.6 volts, the alternator is not working. The system can be diagnosed further by measuring the voltages on the two small wires on the back of the alternator but those readings must be taken with the engine running.