Blinking Headlights

Hi, I have a nagging problem with my headlights on my 1979 Plymouth Trailduster. After I turn on my headlights there is about a 2-3 minute time span before they start blinking erratically i.e.: blink blink......blink blink blink blink.....blink.....blink blink blink, you get the idea, in no special order. I have changed out the light switch on the dash twice and also replaced the dimmer switch on the floor. I have put in new headlights ( there are 4 ), but I only replaced the low beams. I have been told there may be a short somewhere and the headlights have an inline fuse or breaker that is being activated when overheated. I can shut the headlights off when they start to blink and pause for a few seconds and then turn them back on and the cycle will repeat itself in a few seconds. Can anyone help me with my dilemma please? Thanks in advance............"Porky"

porky wrote:
> Hi, I have a nagging problem with my headlights on my 1979 Plymouth
> Trailduster. After I turn on my headlights there is about a 2-3 minute
> time span before they start blinking erratically i.e.: blink
> blink......blink blink blink blink.....blink.....blink blink blink, you
> get the idea, in no special order. I have changed out the light switch
> on the dash twice and also replaced the dimmer switch on the floor. I
> have put in new headlights ( there are 4 ), but I only replaced the low
> beams. I have been told there may be a short somewhere and the
> headlights have an inline fuse or breaker that is being activated when
> overheated. I can shut the headlights off when they start to blink and
> pause for a few seconds and then turn them back on and the cycle will
> repeat itself in a few seconds. Can anyone help me with my dilemma
> please? Thanks in advance............"Porky"

it's a circuit breaker cycling. If you have an ammeter put it inline
with the wire between the headlights and the dimmer switch and let us
know what you find. It's probably a 15 or 20 amp breaker so if current
is less than that everything is normal and you need to replace the
breaker. If higher you need to figure out where the short to ground is
and fix it.

Can you hear the breaker cycling when the lights go on and off? if so,
and you don't have an ammeter, you might also want to try unplugging the
headlights, if the problem persists (i.e. you can hear the breaker
cycling) even with the headlights unplugged, there's definitely a short
that you need to find.

good luck

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

"porky" > wrote in message ...
Hi, I have a nagging problem with my headlights on my 1979 Plymouth Trailduster. After I turn on my headlights there is about a 2-3 minute time span before they start blinking erratically i.e.: blink blink......blink blink blink blink.....blink.....blink blink blink, you get the idea, in no special order. I have changed out the light switch on the dash twice and also replaced the dimmer switch on the floor. I have put in new headlights ( there are 4 ), but I only replaced the low beams. I have been told there may be a short somewhere and the headlights have an inline fuse or breaker that is being activated when overheated. I can shut the headlights off when they start to blink and pause for a few seconds and then turn them back on and the cycle will repeat itself in a few seconds. Can anyone help me with my dilemma please? Thanks in advance............"Porky"

Had this happen also. different vehicle. Found a wire going to tail light had worn through the insulation and shorted to frame (ground). This keep tripping the circut breaker. WW

I used to see that lots on the old beasts. It happens with halogen
bulbs. If you can't find the old style regular GE light bulbs or just
want to run the upgrade to halogen, you need to add a relay to the
circuit or you will blow that breaker. They used to include wiring kits
with halogens back in those days.

You just add a stock bosch relay with direct fused battery power and the
headlight switch with the breaker turns into a low amp trigger wire.

If you already have the old standard bulbs, then you likely have a rusty
contact that is arcing creating heat. Suspect the harness plug for the
headlight switch as having a rotted plug in it. These can be replaced
pretty easy and the socket can even be replaced as a 'Help' brand
product that I have seen on the auto parts store shelves.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

> porky wrote:
>
> Hi, I have a nagging problem with my headlights on my 1979 Plymouth
> Trailduster. After I turn on my headlights there is about a 2-3 minute
> time span before they start blinking erratically i.e.: blink
> blink......blink blink blink blink.....blink.....blink blink blink,
> you get the idea, in no special order. I have changed out the light
> switch on the dash twice and also replaced the dimmer switch on the
> floor. I have put in new headlights ( there are 4 ), but I only
> replaced the low beams. I have been told there may be a short
> somewhere and the headlights have an inline fuse or breaker that is
> being activated when overheated. I can shut the headlights off when
> they start to blink and pause for a few seconds and then turn them
> back on and the cycle will repeat itself in a few seconds. Can anyone
> help me with my dilemma please? Thanks in advance............"Porky"

> porky wrote:
>
>> Hi, I have a nagging problem with my headlights on my 1979 Plymouth
>> Trailduster. After I turn on my headlights there is about a 2-3 minute
>> time span before they start blinking erratically


There's a thermal circuit breaker in there SOMEWHERE that is cycling. It
might be a real overload, but not likely since you say it takes 2-3
minutes to start. Its most likely just the fact that thermal circuit
breakers get trip-happy when they get old and will start cutting out WAY
below their rated current. On most Mopars the breaker is built into the
headlamp switch, but you said you already replaced it. It could be that
the Trailduster has a separate thermal breaker, or it could be that you
have a real problem, or it could be that the breaker in the new switch
is weak also. Trace out the feed wiring to the switch and if you find
the thermal breaker, replace it. If you don't find it and can't find a
short, its a good idea to put the headlamps on relays to take the heavy
load off the old switches and wiring anyway. That will prevent the
breaker from nuisance-tripping. Install new fuses or breakers on the
relay wiring to protect the circuit. Daniel Stern has good relay
installation diagrams on his website: http://www.danielsternlighting.com

http://www.danielsternlighting.com/t...ys/relays.html

"porky" > wrote in message ...
Hi, I have a nagging problem with my headlights on my 1979 Plymouth Trailduster. After I turn on my headlights there is about a 2-3 minute time span before they start blinking erratically i.e.: blink blink......blink blink blink blink.....blink.....blink blink blink, you get the idea, in no special order. I have changed out the light switch on the dash twice and also replaced the dimmer switch on the floor. I have put in new headlights ( there are 4 ), but I only replaced the low beams. I have been told there may be a short somewhere and the headlights have an inline fuse or breaker that is being activated when overheated. I can shut the headlights off when they start to blink and pause for a few seconds and then turn them back on and the cycle will repeat itself in a few seconds. Can anyone help me with my dilemma please? Thanks in advance............"Porky"

Hi, Porky, I've seen older cars that used fuses almost exclusively develop an intermittent short that would keep blowing fuses. When the troubleshooter could not readily find the inter. short, he'd replace that fuse with a circuit breaker from the likes of AutoZone. Then, when it came time for the fuse to blow, the c/b would open until the heat cooled down enough for the c/b to re-close. Saves having to carry fuses to replace at in-opportune times.
If you have such a car with such modifications, it's time to locate that c/b, find the now much-more frequently-occurring short, repair it, & go back using the proper fuse for protection. HTH & good luck, s (You've probably guessed it by now: yes, I did that to my dad's 1976 Luv pickup that was blowing a fuse about once every 6 weeks--caused by a dashlight/taillight circuit that was fuse-protected. No more fuses blew; it fuse was replaced by that c/b which had the same amperage-rating.)

On Mon, 20 Feb 2006, porky wrote:

> Hi, I have a nagging problem with my headlights on my 1979 Plymouth
> Trailduster. After I turn on my headlights there is about a 2-3 minute
> time span before they start blinking erratically i.e.: blink
> blink......blink blink blink blink.....blink.....blink blink blink

Your '79 was originally equipped with low-wattage headlamps; some of the
first halogens, 35/35w low beam. Most of the present-production H4656
sealed beam high/low units are 60/50w or thereabouts. Situation is similar
with the H4651 high beam units. When the wiring was new, it was (barely)
able to handle up to 65/55 high/low plus 60w high. Chrysler has never put
very good headlamp wiring on their vehicles. They didn't in '79, they
didn't in '69, and they don't now. The blinking is caused by the thermal
self-resetting circuit breaker (located inside your headlamp switch)
heating up and cutting out.

Fix it this way:

http://www.danielsternlighting.com/t...ys/relays.html

"Daniel J. Stern" > wrote in message
.umich.edu...
> On Mon, 20 Feb 2006, porky wrote:
>
>> Hi, I have a nagging problem with my headlights on my 1979 Plymouth
>> Trailduster. After I turn on my headlights there is about a 2-3 minute
>> time span before they start blinking erratically i.e.: blink
>> blink......blink blink blink blink.....blink.....blink blink blink
>
> Your '79 was originally equipped with low-wattage headlamps; some of the
> first halogens, 35/35w low beam. Most of the present-production H4656
> sealed beam high/low units are 60/50w or thereabouts. Situation is similar
> with the H4651 high beam units. When the wiring was new, it was (barely)
> able to handle up to 65/55 high/low plus 60w high. Chrysler has never put
> very good headlamp wiring on their vehicles. They didn't in '79, they
> didn't in '69, and they don't now. The blinking is caused by the thermal
> self-resetting circuit breaker (located inside your headlamp switch)
> heating up and cutting out.
>
> Fix it this way:
>
> http://www.danielsternlighting.com/t...ys/relays.html

Hey, Dan, one heck of a nice site. Thanks for your help. s

On Fri, 24 Feb 2006, sdlomi2 wrote:

>> Your '79 was originally equipped with low-wattage headlamps; some of
>> the first halogens, 35/35w low beam. Most of the present-production
>> H4656 sealed beam high/low units are 60/50w or thereabouts. Situation
>> is similar with the H4651 high beam units. When the wiring was new, it
>> was (barely) able to handle up to 65/55 high/low plus 60w high.
>> Chrysler has never put very good headlamp wiring on their vehicles.
>> They didn't in '79, they didn't in '69, and they don't now. The
>> blinking is caused by the thermal self-resetting circuit breaker
>> (located inside your headlamp switch) heating up and cutting out.
>>
>> Fix it this way:
>> http://www.danielsternlighting.com/t...ys/relays.html
>
> Hey, Dan, one heck of a nice site. Thanks for your help. s

Thanks for the "thanks"!