headlight switch

[tony GTS]

ever since i bought my swinger the lights ( all the lights, headlights, sidemarkers, etc..) would go out after about 8-12 minutes of the lights being on and then i'll try and turn the switch on 10 min after they go out the lights will come on but then go out again

well i checked the car today and as soon as the lights go out the back of the headlight switch is as hot as a set of running headers & after it cools down they turn on again.

-why is my headlight switch getting hot?           the fuse doesn't blow just that the lights turn off.

[IL.DART340- 4SP]

Maybe you have lost ground some where check headlight and tail light grounds. IMO replace head light switch.

[nothingbutdarts]

Usually, if you loose a ground, the current running thru the circuit will decrease meaning it would be hard for things to get hot like the switch. (it's the increased flow of current that causes heating.

 It might be a possibility that, the plug in connections on the back of the switch are loose or corroded. That causes excessive heat build up from the bad connection and can cause what your talking about. You could also look @ the bulkhead connector for corroded terminals in it.

 If you have an ammeter, check the connections on it. 

[golferjohn]

I believe the headlight switch has it's own little circuit breaker in it...my old Cougars did and once they start breaking they're never the same.  Just a thought

[PureGTS]

  My Charger had a breaker built in to its headlamp switch. I put driving lights down by the openings for the valance panel, I didn't butcher anything I made mounting brackets for them, so when the lights would start flashing I had something I could use until I got home. I finally took the switch apart and bent the bi-metal strip of the breaker to keep the lights on. Turns out it was caused by a bad connection in the harness plug by the battery. Fixed that and life was good. Switch didn't get hot anymore.
  Modern cars, and my Dart, use relays instead of the switch taking all the load. One of the mag's did a article about wiring the power feed for the headlamps to a relay that was taking the power right off the alternator. This would give the headlamps more brightness due to the shortness of the connection from the supply to the load and te higher voltage supplied there. Doing this also has a side benefit of relieving the OEM switch(s) of the power handling and thereby increasing its life span drastically.

[nothingbutdarts]

  My Charger had a breaker built in to its headlamp switch. I put driving lights down by the openings for the valance panel, I didn't butcher anything I made mounting brackets for them, so when the lights would start flashing I had something I could use until I got home. I finally took the switch apart and bent the bi-metal strip of the breaker to keep the lights on. Turns out it was caused by a bad connection in the harness plug by the battery. Fixed that and life was good. Switch didn't get hot anymore.
  Modern cars, and my Dart, use relays instead of the switch taking all the load. One of the mag's did a article about wiring the power feed for the headlamps to a relay that was taking the power right off the alternator. This would give the headlamps more brightness due to the shortness of the connection from the supply to the load and te higher voltage supplied there. Doing this also has a side benefit of relieving the OEM switch(s) of the power handling and thereby increasing its life span drastically.

                                             

[tony GTS]

where did you get the relay and modern switch from?

[nothingbutdarts]

NAPA sell relays and harnesses. You can turn the relay on with your regular headlight switch. I would think CARQUEST and other parts stores would have them too.

[PureGTS]

It is the original switch. The OEM (original) wiring instead of actually supplying power to the headlamps is used as a signal to turn on the relay. The relay then handles the amperage to the lights instead of the switch in the dash. The relay is available generically at any Pep boys or Auto Zone. It is the same relay used in the "off road lighting kits". As long as the relay has a mounting tab and a 20Amp-30 Amp rating it will work. The relay is a typical Bosch relay with 5, 1/4" pins, out the bottom. Next to these pins (cast intothe plastic) or written on the side of the relay or in a diagram on the packaging will be numbers that match to the pins on the bottom of the relay. These will be the same on all of these style of relays. These are the guide to which pin is/does what.
  What I did, so I didn't have to cut up a perfectly good OEM harness, was get a second set of head lamp sockets to go on to the head lamps. These too are available at Pep boys and like stores. 

I ran a 10-12 ga. wire from the alternator output stud, with a 30A fuse in line, to the #30 pin of one of the relays and jumped the same wire to the #30 pin of the second relay (one relay for low beams, the other for high beams).

I mounted both relays to the core support behind the Passenger's side head lamp bezel near the turn signal. Out of site and protected.

The #85 & #86 pins are the "control" pins; one is positive and the other negative. It doesn't matter which you use for either POS or NEG. In this application, since the "signal" or out put from the switch is POS, we'll use #85 as the "ground" or GND. Run a wire from this pin to the core support.

#86 gets a wire from the OEM headlamp socket that was originally for the low beams. Use a test light to identify the low beam wire from the high beam and GND in the OEM socket. Then stick a "male" 1/4" blade terminal on to a wire and shove it into the OEM socket that was the low beam.

Now when the head lamp switch is turned on to low beams the relay should "CLICK" telling you it is working.

Do the same for the high beams' relay and verify the "CLICK".

Now, use a test light to see which pin, #87 or 87A, on the relay becomes "POS" when the relay "CLICKS" and the headlamps are turned on.

The other will be "POS" when the relay is NOT activated. This is OK since we aren't using it.

Connect the wire from the new headlamp socket(s) to the pin that becomes "POS" when the headlamps are turned on for the low beams. This will match the same hole in the OEM socket that the relay is triggered from.

Add a wire from this same pin and run it to the other side's headlamp.

Repeat process for the high beams and Viola! You are now not only brighter but now your switches are protected from a higher load than they need and will last alot longer than the factory intended.

TROUBLE SHOOTING:

If lights are staying on when switch is off - switch pins on relay (#87 & 87A)

One headlamp brighter than other - check connections at new head lamp socket to make sure the proper "beam" is being activated.

The 30 AMP feed fuse blew - check your wiing; you have a short. The headlamps don't need all 30 amps the fuse can supply; even with the high beams on. If it blows ,there is a bad short! The size of the fuse is big enough to handle the sudden changes and surges the system goes through during normal use; on,off, cycling from lo to hi, sudden on in hi, etc. The only reason it should blow is if there is a dead short. It is oversize to keep your headlamps from going out from "normal" use. It should even be high enough for H2 headlamp systems and "off road" type (100watt) high beams.
  Here's some pic's to make it easier to visualize:

  It sounds harder than it really is. Unless you installed your Classic Auto Air A/C before you tried to do this. Then it can complicate things.