I have a 72 duster with all lights that pulsate at idle, and even more when the rpms go up.(they strobe) not just brighter with rpms and dimmer at idle, they actually pulsate. I ran the wire from the alternator to the battery side of the solenoid, thinking this may stop the problem but it didn't help. I unplugged the voltage regulator and the pulse stops, could this be a bad regulator/alternator (regulator/alternator is new). What could be causing this problem.
Pulsating lights
- Thread starter 6twister
- Start date
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hcarr
Well-Known Member
Sounds like the voltage reg. is not getting a good ground. Try scrapping some paint off the firewall to get a better ground. It has worked for me before.
Howard
Howard
slantsixdan
=..=
It's not unusual, but it's not normal. And while a solid-state regulator will usually be steadier than a points-type unit, it won't solve the other issues that contribute to erratic voltage regulation. The wiring all has to be in excellent condition including all the connections, and the regulator, alternator, and battery ground plane all need to be tied together electrically. Run a new 14ga wire from the "GRD" hole on the back of the alternator housing (to the voltage regulator base, and from the voltage regulator base to the battery negative terminal. See here and here
Well Dan I did everything you said, and still no go. I ran the wires like you said from the ground off the alternator to the mounting screw on the regulator, from the regulator to the neg side of battery terminal, and I still have hollywood lights. I changed the volatage regulator, and that didn't work either. I pulled the bulk head plugs out and replugged them in, taking and small screw driver and pushing on each of the terminals to make sure they are plugging in tightly..still no good. Any more ideas you can send my way will be appreciated. Do they make a terminal cleaner that i can spray into the bulk head terminals that will clean them? Oh I also cleaned the grounds on the front and back light harness where they ground to the body. Brian
slant6/4speed
Well-Known Member
How good is your body ground? Not the big (black) battery cable to the block but the smaller black wire coming off the battery and going to the body/fender/radiator support. How fast is the pulse?
that wire is good,,I took a razor knife and scrapped the terminal and scrapped the radiator support to the metal. Its a new mopar battery cable with the ground molded in the battery terminal, so that should be ok. It pulsates only at high rpm,,not idle, and I would say it pulsates about 2 times a second.
slant6/4speed
Well-Known Member
OK-go out were it is dark raise the hood and look at the alternator to see if you can see any sparking (inside the alternator) that keeps time with your flicker/pulse. You may see some sparking at the brushes(normal). Other wise it has to be some thing with the regulator or its wiring. PS if you see a lot of sparking in the alternator it usually means worn out brushes.
Alternator is new. I will try the dark test tomorrow. If I unplug the regulator the problem goes away. Another thing happened I might mention. When I rrun the car for along time the left turn signal doesn't work,but the right side works fine, however when I put the signal on left, both tail and front turn signal stays on bright without the flashing. Let the car cool down and the left signal works again.
nothingbutdarts
Well-Known Member
I agree here with the bad diode/diodes.
Do you have a voltmeter? Use the A/C scale on the low setting and check it while the engine is running. A good alternator will have no A/C voltage.
The 2 could be related.
You could pull the signal fuse, check condition, then pull the flasher and check condition.
Question.. do the oem gauges work ? If the original gauge voltage limiter is there, Unplug it. There should be a paper insulater between that limiters' noise supression capasitor lead and the printed circuit board. I remeber seeing a short there. I dont recall the symptom details. I've seen the oil pres' sender shorted to the distributer housing too.
We'll find it
When I first seen the title I thought...
UFO
UFO
I checked the alternator output with a multimeter set on 200 vac, put the red probe on the battery side of the alternator and the black probe to the engine for a ground, and it shows between 27.0 - 30.0 volts and jumps up for a split second to 121 volts and back down to the 30.0 volt mark, and does this repeatly every 5 seconds or so. Whats up with that.?
nothingbutdarts
Well-Known Member
A good quality alternator should not be putting out that kind of A/C voltage!
I hate to say it but I might try a new alt. The diode trio is going "south"
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