PDA

View Full Version : Flickering Head Lights?


SoCalSprinter
10-09-2013, 04:29 PM
Last month my headlights began to dim whenever I put a load on the electrical system such as using power windows or hazard lights.

Today My headlights & Becker radio display are flickering with the RPM's of the engine.

Is this as simple as a bad alternator, or is there something else I should consider? Bad ground? If so where might I begin to search?

My van is at 92,000mi on all original parts.
All suggestions are welcome.
Please & Thank you





2004 NAFTA T1N 140"
10-Passenger Wagon w/ rear A/C unit.
Los Angeles, CA

autostaretx
10-09-2013, 04:44 PM
Is this as simple as a bad alternator, or is there something else I should consider? Bad ground? If so where might I begin to search?

Yes.

The *first* thing to check is the connections to the battery terminals. A loose clamp (or contamination) can cause all of your symptoms.

Then check the battery (perhaps it has a damaged inter-cell connection).
Check fluid levels (if possible).
Then engine-to-frame and engine-to-negative post voltage drop (when running/charging).
If you see *any* significant voltage drop (0.2v or more), that hints at bad grounding straps.

Yes, it could be a failing alternator, or bad alternator over-running clutch pulley, or simply a loose belt.
But an amazing number of these issues are the result of a loose connection to the battery.

--dick

SoCalSprinter
10-20-2013, 03:47 AM
So in the end all battery connections were good and the alternator tested good. I had the main serpentine belt replaced and flicker problem went away.

SoCalSprinter
10-20-2013, 01:01 PM
I spoke too soon.
Flicker is back

lindenengineering
10-20-2013, 02:54 PM
You need to check the primary circuits for high resistances, certainly include the battery itself like drop and charge holding, internal resistances etc, then if all that checks out good focus in on the alternator.

The diode pack might be phasing and I have found due to its positioning on the engine mag chloride gets inside the machine corroding the ground section of the case where the diodes are mounted.
Dennis