Dash lights flickering

[ricardoguitars]

Hello everyone, the dash lights in my 1995 2.3 XL started flickering at idle a few days ago, the battery is old, label says it was installed in 2015, I had forgotten to turn off the aftermarket radio a couple of times and it has ran out of juice, after recharging it works fine. Can the issue be the old battery, or the alternator failing?, I bought this car used a year ago and I don't know if the alternator has ever been rebuild.

Thanks for the help.

 

[Dirtman]

The battery does nothing after the truck is running. The alternator takes over at that point. Measure your battery voltage with the engine off, then measure with engine running. You should have 12.2 - 12.8 with the engine off and then get a spike to around 14.8 when the truck first starts which should slowly drop to about 13.6 after 10-15 minutes. If you don't see that voltage spike after starting the truck its very possibly a failing alternator or bad connection. If the voltages all look good I would look for a physical problem with the dash wiring. Loose ground wire etc.

 

[ricardoguitars]

The battery does nothing after the truck is running. The alternator takes over at that point. Measure your battery voltage with the engine off, then measure with engine running. You should have 12.2 - 12.8 with the engine off and then get a spike to around 14.8 when the truck first starts which should slowly drop to about 13.6 after 10-15 minutes. If you don't see that voltage spike after starting the truck its very possibly a failing alternator or bad connection. If the voltages all look good I would look for a physical problem with the dash wiring. Loose ground wire etc.

Thanks Dirtman, I will do that test.

Cheers.