Voltage Drop When I turn on Flashers or Signal Lights

71225 · Jul 5, 2007

My 87 YJ has been sitting for a few months. Finally started it back up. Ran a little rough but is smooth now.

One thing I noticed is when I turn on the parking lights or just use the flasher the voltage indicator and oil pressure gauge drop. This also affects the radio and the front speakers have ceased working. Turning on the fan also affects the voltage.

I checked the Engine to body ground and Battery to engine ground and it all looks good.

Voltage at the cigarette light can drop as low as 1-.6V compared to 13.8 at the battery while running.

Are there additional ground points under the dash I should look at? Any help appreciated.

Thanks

Steve

Ares · Jul 5, 2007

I would have your alternator checked out if it were me. That could be indications of it failing

learfxr · Jul 5, 2007

Sounds like the voltage regulator in the alt. Hook the meter to the batt and watch what happens when someone else activates things. My ford ranger has been week for about 2 years. It still charges fine, but it dims when you drop down to idle at night with the lights on, then it comes back up after a second.

70sElvis · Jul 5, 2007

I know most newer model alternators have the voltage regulator built into them but I am not sure about your model. If you have an external voltage regulator, take both of them to someplace that can check them for you.

71225 · Jul 11, 2007

Thanks guys. The voltage at the battery from the Alternator seems OK and the other devices not activated from the OEM dash switches seem ok. I swapped out the Alternator ($68 at autozone) and the problem remains the same.

I'm going to check the grounds on all lights and remove the dash to look for corrosion at ground points.

Voltage Drop When I turn on Flashers or Signal Lights

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