Pulsing/Flickering lights

[sconner]

I have read several threads but none have addressed the issue I think I am having.

2002 Ford Ranger 4.0L 4X4, I do not appear to have DRL's no lights on unless I turn the switch.

All lights (dash, dome, tail, head, fog) pulse at a very fast rate. Obviously more noticeable at night. Some times it even feels like the engine pulses with the lights on.

Have had the alternator checked at two different places, both checks show diodes good, regulator good, out put of 14.5 volts and with all lights on 40 amp output.

So do I have DRL and maybe the module is completely bad so they don't come on?

If I don't have DRL what could cause the pulsing?

Thanks for any help,
Scott

 

[1994Ranger$$$pit]

I have the same issue except the engine pulsing.
Been like that since I changed my alternator a couple years ago.
Very quick pulsing even though the alternator works fine for charging the battery.
And the dash volt meter is in specs.

 

[Earl43P]

Disconnect the Battery, then disconnect the + lead to the alternator (protect it from touching anything while that is disconnected!).

Reconnect the battery and start the truck and see if the pulsing goes away.
If so, replace the alternator.

 

[sconner]

Thanks Earl,

I will give your suggestion a try.

 

[swynx]

My Saturn does this every time I press on the brakes or hit the blinkers it starts

 

[adsm08]

Bad voltage rectifier in the alternator. Cars run in dc voltage, alternators make ac voltage. What you are seeing is the current switching directions. Your house lights do the same thing but the frequency is faster than your eyes can pick up.

Postin' from teh Galaxy