wonderfull electrical issures....

[mkealz]

...are not my fav.. No rear taillights, (brake lights work), no side lights, no interior dash lights, no gas gauge, tach or clock....all not working. Been told there is a ground issue...but not sure where to look or start...any suggestions? Car is 73 Challenger 340...Thanks

[matador60]

I would believe its more likely a power issue. the taillights are grounded by the holder to the body as are the side lights. get a diagram and check power threw the switch for the lights.

[mkealz]

ok...headlights and dome light work..so I presume switch is good.

[dusterbd]

there are about four different circuits inside the switch. just because some work does not mean that others will.
to diagnose:
first, get a schematic. ebay normally sells color ones for pretty cheap.
while youre waiting on that to come in, check all your fuses. a lot of the old fuse panels corrode up and cause intermittent problems. so clean the terminals, and check the fuses. after that, i would start cleaning all the grounds from the dash board back. anywhere there is a bolt through a wire, its normally a ground. the wiring schematic should help you out. all thsi should bring your system yup to snuff enough to start diagnosing it.
under your left side kick panel should be a connector. check the voltage through this connector in your rear running light circuit and fuel tank sending unit lead. if no voltage, go upstream into the dash and try from out of the switch. if no voltage, replace switch. if voltage out of switch, but none, replace wire to connector.
the long and the short of it is to start with all your information, and go connector by connector with a good volt meter, working from the source of the voltage out. youll beat your head against the wall trying to go from the last spot on the circuit back to the source.
make sure to clean and protect all teh terminals as you go, and replace anything that looks scary/damaged
hope this helps. you may also try to talk with BJSRACING for his advice. hes the guy i talk to when im stumped.
Michael

[451Mopar]

Someone had a simular problem. I think the power to the headlight switch was gone, possably a blown fuse (I don't remember), but I think this is the same circuit that powers the cigar lighter too.
From my '71 FSM the wire is "L8-18P" (18AWG / Pink wire) to the headlight switch from the fusebox. The Cigar Lighter is X1-16R (16AWG / Red wire.)
Both these wires connect at the same point on the fuse block, looks like the corner away from the Horn Relay/Key Buzzer?

[cudabob496]

Recommend the "bypass the bulkhead connectors trick." Run a wire with a fuse from the alternator output directly to the 12v post on the starter relay. I used 10 or 12 guage wire with a 40 amp inline fuse. Bypasses old crusty connectors.

[mkealz]

Thanks guys....I am going to gut the interior so will have plenty of room to check out wiring under dash....all good advise as usual...I put in a new sending unit with ground strap...so maybe it is the fuse terminals...as I have no cig lighter either...the tach not working stumps me...not sure why that won't run...but winter is coming...lots of time to fix up the old car....

[mkealz]

Cudabob...What does the by pass accomplish...new to this...Thanks..MK Farmington, MN.

[cudabob496]

Originally Posted by mkealz

Cudabob...What does the by pass accomplish...new to this...Thanks..MK Farmington, MN.

Read through the below link. Let me know if you have any questions and I will try to answer.



http://www.cuda-challenger.com/cc/in...?topic=34673.0

[ehostler]

It really sounds like the headlight switch is beginning to fail, due to the increased load of small wires that produce more resistance/load as the system gets old and corroded bulkhead connectors that also produce more resistance/load.

[cudabob496]

By the way, because my headlights drew 10 amps, I installed a new headlight switch, and used relays, and ran new 12 guage wire to the headlights, and the amp load for the headlights is now 3 amps instead of 10 (I have almost all the electrical load going through an after market amp guage, so I can measure all loads). That old wiring, along with cruddy connectors in the bulkhead, really makes for poor conductivity.

[mkealz]

Does anybody know where I can buy a new headlight swithch for my 73 Challenger....I checked with Year One and they do not reproduce these....I have also checked with my local Carquest and nothing....Thanks

[TrashedCharger]

That is a headlight switch without a doubt. Some circuits of the switch will continue to work while others won't, or even worse, will work intermittently.

I just finished restoring the dash of my Scamp this past weekend. I discovered that most of the problems that the car had electrically could be traced back to a single ground wire.

I had always thought that the poor steel pins in the bulkhead connector were to blame for the typical headlight dimming in my car and just about every single other A body that I have ever seen, but I found that it was a combination of a few things.

There is a lot on that car that runs through the ignition switch. Even the head and tail lights which still work without the ignition on, they still run through the switch. Also, all of the dash lights and everything else in the dash, including the windshield wiper switch and heater controls also run through the ignition switch in some manner.

There is a ground wire that goes from one bolt on the bottom of the steering column mount bracket, to the steering column mount studs that go into the body of the car. I did an experiment and discovered that none of the things that run through the ignition switch work when I disconnected this small wire.

When I went to reassemble the column, I noticed that there was paint on one of the eyelets of the ground wire and that the contact surface of the eyelet on the steering column bracket was originally painted. My guess is that the electricity was depending entirely on the threads of the bolt that were contacting the inside of the eyelet for the ground on the entire blanket of circuits running through the ignition and grounded to the steering column!

After I sanded and painted the bracket to go under the restored column, I masked off and cleaned the entire area of the eyelet contact surface on the column bracket, down to bare metal before mounting the ground wire. I also installed a new light switch (which was previously blowing my dash bulbs) and everything, including my ignition is running stronger. My headlights no longer dim at idle and my dash has absolutely no problems.

I'm planning on going back under there and making a new ground strap for the column out of 6 gauge wire, brass eyelets, soldered and heat-shrink tubed, but even with the clean steering column bracket ground surface alone, even before I put the new light switch in made a night/ day difference.

This ground wire on the column may be the cause, because there is so much that isn't working, but I would still suggest investing in a new light switch.
While this stock ground wire sucks, looking at the bright side, I've also learned a new, very mean trick to pull on my fellow mopar enthusiasts.

Another thing you may want to check is your Ammeter wires that go from the bulkhead connector to your ammeter (alternator gauge). I know that especially on the older cars, the positive wire fries itself and can either kill the engine or work very poorly. I've seen them cause problems with tachometers alone as well.

The best thing you can do is check that column ground, check the ammeter wires and replace anything questionable. If you can find a headlight switch, do it right away. They are notorious for blowing fuses.

I'm still looking for an outlet source for your new headlight switch, but in the mean time, you might try one of these-

http://cgi.ebay.com/ebaymotors/Headl...spagenameZWDVW

http://cgi.ebay.com/ebaymotors/New-H...spagenameZWD1V

I take it that these are tough to come by.

[cudabob496]

Originally Posted by mkealz

Does anybody know where I can buy a new headlight swithch for my 73 Challenger....I checked with Year One and they do not reproduce these....I have also checked with my local Carquest and nothing....Thanks

http://cgi.ebay.com/ebaymotors/Headl...QQcmdZViewItem

[mkealz]

Thanks again ...you all are so dam helpfull...I really appreciate it. I will be bringing my Challenger to my shop....and I am gutting the interior...so I will look for the items you told me about.....I found a used switch for $99 ..but think that maybe a bit steep for used...and not sure if it even works...Thanks again...

[mkealz]

trashed charger...you can quit looking ...thanks to Cudabob...I found one for $40...Thanks again...and keep in touch...you are helpful...