Tick Tock sound by heater controls and the lights dim

[Tonefiend]

Today I drove the Challenger to work.  Coming home in the evening I hear a Tick Tock sound behind the dash by the heater controls.    The tick tocks are 6 seconds apart and last 1 second.  During "tick" the headlight and dash lights dim.  The dash light over the heater controls goes out.  During "tock" all lights come on full strength. 

Here is where it gets weird.  With the dash lights turned off the light over the heater control comes on during the "tick"

It appears the sound is coming from right where the light is over the heater controls.  It's dark out and i have not had time to check it out back there.  Any ideas?   

[Moparal]

you dont smell anything burning do you?  If so, dis connect your battery tonight untill you get the switch cover off. Something is drawing serious amps

[Giveitawack]

Try and disconnect the wiper motor connector from the bulkhead and see if it stops.

[Skunkworks Challenger]

I would suspect a circuit breaker cycling on and off in response to a short circuit.  PK

[Tonefiend]

Thanks for the quick replys.  I will go disconnect the battery.

A bit more info.  My last battery lasted 9 months.  The voltmeter flickers with the blinkers, brake lights and any use of current.  The lights also dim and get brighter.   Something is wrong somewhere.   

Last week I cleaned up the taillight wiring. It was a mess, held together with duct tape.  I soldered and shrink tubed all the breaks and cleaned the contacts and replaced the bulbs.  They now work fine.  There is a mess under the dash. Cut wires and an aftermarket radio. 

I will try the wiper motor, you know I turned the wipers on by mistake when I started the car in the dark and wanted to see if the dash lights were on as bright as possible. 

[Skunkworks Challenger]

It's time to get really freightened about FIRE!  In restoring my Challenger I found traces of electrical problems and feel lucky the car did not burn.  With the symptoms you describe it's time to take the bull by the horns and redo your electrical system.  Not a fun thing to do and can get expensive but do you have a choice?

[Bullitt-]

There is a second blinker for the emergency flashers over that way (at least on a '73)....
just might be your flasher switch is on or shorted.

[Tonefiend]

There is a second blinker for the emergency flashers over that way (at least on a '73)....
just might be your flasher switch is on or shorted.

Yes it sounds like a binker.  Stupid question, where is the emergency switch?  Maybe I hit it by mistake. 

[Giveitawack]

E-flasher knob is between the ignition key and the steering wheel crush can.

[Tonefiend]

Thanks, now I remember seeing it there.   I doubt I turned it on by mistake, and the lights never flashed.  Something is going haywire, now I know where to look.  With luck that is where the short is thats causing my battery to die.

The electrical system is the next thing I am working on.  Next up is to clean up the wires under the dash.  Get rid of the Audiovox radio and run my electric choke off the fuse panel instead of the ballast resistor. 

[Giveitawack]

I had a tic toc sound in that area. It started after I connected a restored wiper motor. I disconnected the wiper motor bulkhead connector and it stopped.

[Tonefiend]

The wipers don't clear the hood.  When I turned them on I wonder if I smoked the wiper motor when they got stuck...  Tomorrow I will unplug it and see what happens.

[nqkjw]

Try and disconnect the wiper motor connector from the bulkhead and see if it stops.

Spot on!!!
EXACTLY the same symptoms with mine and pulling the plug on the wiper switch has stopped it.
I know my wiper switch is crook so it didn't surprise me.

I was guessing the cycling of the problem has something to do with the wiper park function?

[Giveitawack]

Yeah, I also thought of the parking function. Either that or some ground problem.
I put in another wiper motor and everything works fine now.

[dodj]

Self resetting breaker in the switch. You best find the cause of the high load b4 it causes other problems. Giveitawack's suggestion of unplugging the wiper motor would be a good start. I would avoid driving it until you find the fault.

Your lights are dimming when the breaker closes because the high current demand of the fault is lowering the electrical system voltage - the alternator and wiring can't keep up with the current demand, lights dim. When the breaker opens and the fault is disconnected from the alt, the voltage goes back to normal. the breaker opens and closes based on the heat caused by the current flowing through the breaker.