The B Body Titanic is sinking, please help

Cordoba Kid · Aug 11, 2015

So I am the proud owner of a 1977 Chrysler Cordoba. Corinthian bucket seats with center console and floor shifter, 360 4 barrel from California so it doesn't have the lean burn. It is pretty much one of my dream cars. But it has developed a few issues. Whenever I pull my headlight switch I blow a 20 amp fuse that controls my radio light, my shifter light, my front blinker indicator/parking lights, my tail lights, my opera lights, and my chronometer. I cannot remember right now but according to the 1978 manual it is the number 8 fuse and I don't see why 1 year in the same generation would change the fuse box. I disconnected the clock and checked the shifter light to make sure it wasn't grounding out on something. They both didn't change a thing. Now, when I activate a blinker or hit the brakes the proper lights will light up. Can anyone point me in the right direction or tell me anything that may be wrong? I don't mean to type so much but I'm trying to be thorough in my explanation of the issue.

And if anyone has any tips on how to get the gauges lights working that'd be great. They used to work every now and then but now they don't work at all.

Richard Cranium · Aug 11, 2015

The car is telling you that it wants to self destruct. You should take its advise.

moparcrazy · Aug 11, 2015

"Start with replacing the head light switch"...just unplug it from behind the dash (without removing the old one) and plug in the new one from behind.

mightymopar · Aug 11, 2015

Richard Cranium said:
The car is telling you that it wants to self destruct. You should take its advise.

Not very nice, Richard.

ODZKing · Aug 11, 2015

moparcrazy said:
"Start with replacing the head light switch"...just unplug it from behind the dash (without removing the old one) and plug in the new one from behind.

I agree, inexpensive way to start. NAPA Part Number: ECH HL6548 $17 and change.
If it still does the same after, then you go from there. But eliminate that first.

PP1RT · Aug 11, 2015

If you have any hair just go to the barber and have it all cut off because you may pull it all out before you find the problem.

Check your grounds.

Like was said start at the light switch. If that's ok then start tracing all your wiring to find the short. Firewall area, hot exhaust area, under the carpet, under the rear seat?

ODZKing · Aug 11, 2015

Well, it isn't that difficult but it could be time consuming. After you get the HL switch out of the picture start by unplugging items to trace the specific area of the short. What did you move around recently? Did you do anything under the dash? What has changed before this problem arose.
Unplug the radio (light). Then what you can't unplug pull the bulb. Have a good supply of fuses. When it doesn't blow you know you are in the general area of the short. Some shops have a short tracer too but clearly that will cost ya some $$. But if you don't have the time to fool around there is another solution.

440roadrunner · Aug 11, 2015

moparcrazy said:
"Start with replacing the head light switch"...just unplug it from behind the dash (without removing the old one) and plug in the new one from behind.

I agree. Start with "how these work." The dash lights on a Mopar have "been a trick" ever since the early days. The headlight switches have TWO power sources, one to supply ONLY headlights, and the second comes FROM THE tail light (other) fuse. This is the fuse you are blowing

Dash light (dimmer) power comes FROM that tail fuse. You turn on the HL switch, twist and adjust the dimmer control, and that power now LEAVES the HL switch on a TAN wire to the dash lamp (inst) fuse in the fuse panel. The output of this fuse supplies ALL dimmer controlled lighting on ORANGE wiring.

You aren't blowing THAT fuse because the trouble is BEFORE that.

Much of the stuff you mention, tail, opera, etc, is supplied off the SAME fuse which you are blowing, but all that stuff is working with the light switch off

There is only two possibilities as I see it...........

Either the tan instrument lamp wire going from the dimmer control to the fuse panel is shorted to ground........

Or the HL switch is bad. The dimmer control is probably screwed up, and has "grounded out."

Richard Cranium · Aug 11, 2015

mightymopar said:
Not very nice, Richard.

I thought I was being nice?

Coyoteduster · Aug 11, 2015

mightymopar said:
Not very nice, Richard.

I was afraid of this ....., looks like all the Hellcat owners are turning into Richard Craniums. :laughing6:

Richard Cranium · Aug 11, 2015

Coyoteduster said:
I was afraid of this ....., looks like all the Hellcat owners are turning into Richard Craniums. :laughing6:

But....I've always been like this.

Cordoba Kid · Aug 11, 2015

The headlight switch was dirty. So maybe it is time to replace it but everything is fine now it seems. Thank you to everyone who helped out.

Coyoteduster · Aug 11, 2015

Richard Cranium said:
But....I've always been like this.

Very good, carry on .... :icon_mrgreen:

ODZKing · Aug 11, 2015

Yep, for the price, why wait until it is really a problem. Replace it. Any parts store should have one. Have them cross the NAPA # I posted

aldal · Aug 11, 2015

Cordoba Kid said:
So I am the proud owner of a 1977 Chrysler Cordoba. Corinthian bucket seats with center console and floor shifter, 360 4 barrel from California so it doesn't have the lean burn. It is pretty much one of my dream cars. But it has developed a few issues. Whenever I pull my headlight switch I blow a 20 amp fuse that controls my radio light, my shifter light, my front blinker indicator/parking lights, my tail lights, my opera lights, and my chronometer. I cannot remember right now but according to the 1978 manual it is the number 8 fuse and I don't see why 1 year in the same generation would change the fuse box. I disconnected the clock and checked the shifter light to make sure it wasn't grounding out on something. They both didn't change a thing. Now, when I activate a blinker or hit the brakes the proper lights will light up. Can anyone point me in the right direction or tell me anything that may be wrong? I don't mean to type so much but I'm trying to be thorough in my explanation of the issue.

And if anyone has any tips on how to get the gauges lights working that'd be great. They used to work every now and then but now they don't work at all.

You've gotten some good advice and one thing I would like to add is get a wiring diagram and take some time when you can and really study it and picture in your head all the different components and how they interconnect....that's what I did and it really helped me understand things with my project.

Bruzilla · Aug 14, 2015

I had a similar problem on my Roadrunner. Did all the usual checks, and was about to start running new wires to all the lights when I happened to look through the gap between the body and rear bumper and saw a glint of copper showing on a wire where it passed through a hole in the bumper. Turned out over the years the wire had chaffed in that one tiny spot and was shorting out the lights. So I would suggest examining every wire, especially where it could rub on anything, and see if you have a bare area that's shorting.

As for dash lights, I had an issue with those as well. I ended up just running a wire from the dash lights to the wire for the radio lights. Worked just fine.

The B Body Titanic is sinking, please help

Cordoba Kid

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Richard Cranium

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moparcrazy

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mightymopar

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ODZKing

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PP1RT

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ODZKing

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440roadrunner

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Richard Cranium

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Coyoteduster

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Richard Cranium

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Cordoba Kid

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Coyoteduster

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ODZKing

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aldal

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Bruzilla

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