Lost dash lamps, parking & tail lamps

dplotkin

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Good to meet you folks. Joined today. I own a 68 New Yorker 2 door hardtop. I lost my dash, parking, side marker & tail lights intermittently over a 1 day period and the next day they were out and not coming back. Everything else works. I have no power on either side of the Inst/tail fuse. Fuse is good. I pulled the back of the fuse block open, all looks good. I wiggled the plugs on the back of the headlamp switch and dimmer, nothing. Where do I begin looking for what looks like an open circuit, or is this a burned out headlamp switch?

Clue? About two years ago I re-lamped all 4 side markers which were burned out. They worked fine until now, wondering if the new load finished off the switch contact? Wiggling the headlamp switch toggle to find a hint of trouble comes up empty.

Looking forward to hearing from you C body guys, glad I found you.

Dan

Chrysler 18.jpg
 
First thought, the dimmer. Second thought the headlight switch. After that get out your volt meter and check bulb sockets for power. My favorite "bad ground" detector is 25' of lamp cord wire with an alligator clip on both ends. Clip one end to the -ve battery post. Clip the other end to the socket or ground of the light being tested. If the lamp lights, the socket ground is broken. If the light s dim and touching it with your ground tester makes the light nice and bright, you have a crappy ground.
 
Welcome!
Beautiful New Yorker!
I just upgraded my fuse box to bladed fuses last week because of a tail light/ dash circuit problem. The fuse holders just had enough corrosion to cause problems, even after my best efforts with a wire brush.
Not sure if you know about online FSM, nut trying to chase circuits without a wiring diagram sucks.
MyMopar - Mopar Forums & Information - Service Manuals
You can try downloading a FSM here, but it looks like they skip from 66-70.
Maybe if you dig harder you can find one for a 68.
 
If you don't have power to the fuse, then it's not the switch.

The feed from the battery goes to the fuse block and then to the headlight switch etc. Bet the cigar lighter doesn't work either....

I don't have a good wiring diagram for a 68 and there isn't a factory service manual available for download, so that should be your first priority is to obtain one. I suggest the ones on CD 1968 Chrysler Shop Manual CD 68 Imperial 300 New Yorker Newport Repair Service | eBay

The "MyMopar" link listed above does have a 68 Plymouth FSM though and a Fury wiring diagram is going to be close enough to get a look while you are waiting for your FSM to arrive. Print out the pages and start highlighting the wire runs and that will give you an idea where to look.

Chances are you have some sort of wiring issue from the fuse block to the infamous wire splice. It may go farther than that, into the bulkhead disconnect, but I would start at the (probably) red wire out of the fuse block and see where it takes you.

Don't start throwing parts at it (like the light switch) until you've figured out exactly where the problem lies.
 
If you don't have power to the fuse, then it's not the switch.

The feed from the battery goes to the fuse block and then to the headlight switch etc. Bet the cigar lighter doesn't work either....
.
Not so fast John, I know the power for some goes to the headlight switch and then to the fuse block and on to the lamps. Not sure on his model, don't have a schematic in front of me for that one.
 
Not so fast John, I know the power for some goes to the headlight switch and then to the fuse block and on to the lamps. Not sure on his model, don't have a schematic in front of me for that one.
Yes, it does, but that feeds the headlights only and has a circuit breaker built into the switch. The other lights (tail etc.) are feed off the fuse block.

Basically it's two separate circuits with a double pole switch.
 
Test the fuse, it might look good but it could of came unsoldered at one of the ends
 
Test the fuse, it might look good but it could of came unsoldered at one of the ends
Fuse is not the problem. I have no power on the line side of the fuse (tan wire) I have gone inside the fuse block & everything appears OK. I have a shop manual and am having trouble following it, its a reproduction & not too clear. From where does the tan wire get its feed, light switch? I have headlights. I have everything except tail lamps, marker lamps, parking lamps & dash illumination. Where is the infamous splice? I see a lot of orange wires going to one point, where is that?

Dan
 
Fuse is not the problem. I have no power on the line side of the fuse (tan wire) I have gone inside the fuse block & everything appears OK. I have a shop manual and am having trouble following it, its a reproduction & not too clear. From where does the tan wire get its feed, light switch? I have headlights. I have everything except tail lamps, marker lamps, parking lamps & dash illumination. Where is the infamous splice? I see a lot of orange wires going to one point, where is that?

Dan
The tan wire does get its feed from the light switch, but that gets the feed from the purple wire coming off fuse "E" shown in the diagram. It's kind of a daisy chain were there's an extra fuse after the switch and before the lights.

So... the fuse could blow for the dash lights and only the dash lights would be out... But... If the fuse for the tail lights blew, you would not have dash lights and tail lights. Follow me?

Remember when I said "bet the cigar lighter doesn't work"? If you look at the diagram (68 Fury was all I had but it should be the same). See the red box? That is the feed for three fuses. If you don't have power there, you don't have power to any of those fuses.

So... If like you say "I have everything except" and the cigar lighter or dome light works (fuse "D") this is really starting to point at a bad fuse for the tail lights... Or an issue with the fuse block.

fury dash.jpg
 
Looking at the pic, the red box obscures the split between the two "bus bars" in the fuse block and I don't want to throw more confusion into the mix. One bus bar (on the left) is switched on with the ignition switch and the other (tail lights etc) is powered all the time.

fury dash 2.jpg
 
OK, John, I follow you. Using a incandescent test light, ignition on both sides of every terminal in the fuse block is hot except the instruments, both sides dead. Which fuse is the rear running & front parking lamps/side markers? I suppose it could look hot to a low draw test light but not pass the current to run all those lamps, there's a lot of them. I really appreciate your help. This went rather sudden, seems a munged up switch would act up before laying down.
 
I have no power on either side of the Inst/tail fuse.

Using a incandescent test light, ignition on both sides of every terminal in the fuse block is hot except the instruments, both sides dead.

So, you have power to the tail light fuse or you don't??????

The fuse marked "E" is the tail lights, but in your first post you said you don't have power to the tail light fuse.
 
So, you have power to the tail light fuse or you don't??????

The fuse marked "E" is the tail lights, but in your first post you said you don't have power to the tail light fuse.
Yes. Sorry for not being clear. All fuses are good and all terminals are hot except for G. The feed side of this fuse holder is dead.

Dan
 
Yes. Sorry for not being clear. All fuses are good and all terminals are hot except for G. The feed side of this fuse holder is dead.

Dan
That changes everything.

So... Now it could be the switch.

Check to make sure the plug is on all the way.
 
That changes everything.

So... Now it could be the switch.

Check to make sure the plug is on all the way.

Yes, I've done that once but I'll do it again when I get back inside the fuse block. I got the car with the blower fuse terminals melted pretty good, fuse loose. I repaired that years ago but I'll go back & look at that. I suspect the switch, the new load of 4 marker lights introduced recently after changing the bulbs may have finished off the contacts. I saw one on eBay for $175. Wow.

Dan
 
Not so fast John, I know the power for some goes to the headlight switch and then to the fuse block and on to the lamps. Not sure on his model, don't have a schematic in front of me for that one.
Now I understand what you are saying here after looking at the wiring diagram. You are correct that the dash lights fuse is fed by power from the switch. Of course, the switch does get that power from the tail light fuse.
 
Gentlemen:
Had the weather to fool with it again yesterday. Started with inoperative dash illumination, parking lamps, side markers & tail lights. Everything else throughout the car working. Ignition on, both bus bars are hot and I have 12 volts on the load side of each fuse EXCEPT Inst lamps, dead on both sides. For ha ha's I pulled all the fuses out, wire brushed the terminals, replaced all fuses with new ones, same result. Goofing around with the switch & dimmer I try to find an intermittent point or any evidence the switch has a failing contact. Nothing. I jumped 12 volts over to the instrument circuit, tan wire, and everything works (but is running through rheostat so I cannot leave it that way. So I have continuity through the circuits in question. Then I drove the car 10 miles with the headlights on, stopped to visit a friend working on his 67 Camaro for about 25 minutes and when I got back in the SOB's were working! So now I wiggle the switch toggle & rheostat to see if I can make her fail and nothing, no blinking, no evidence of a bad switch. WTF! I think its a switch, but it doesn't act like one. I put it away working, who knows what I'll find.

Thoughts?

Dan
 
I would highly recommend this:

1968 Chrysler Color Wiring Diagram - ClassicCarWiring

Spend the $30 and get the large one sided version.

An absolute must for chasing down electrical issues.

And for making sense of it all.

What's the history of the car? Untouched one owner, train wreck, lot's of creative electrical "engineering"?

My initial speculation would be a loose connection/switch, weak/lost ground, or chafed wire somewhere in the circuit.

The above could all be affected by the opening and closing of the driver's door.

Or even hitting a bump, shifting out of park, taking a turn, etc.

Make sure that all the parts of the instrument cluster are properly installed and tight, it is grounded to the dash frame.

I've had headlight switches do odd things before the internal circuit breaker finally failed.

This is probably unrelated, but something to file away for future reference:

I had the ammeter gauge fail in the black 2DHT. Before a complete loss of power, there were odd symptoms of a bigger issue. The fuel gauge would come and go, the headlight switch would trip repeatedly, super bright dash lights, rare starting issue, etc.

Once removed and tested, I discovered that one of the connecting posts had worked it's way loose enough to lose continuity. Over time, the connection separated. A light twist with pliers restored it.

I installed a known good ammeter and all was fine again.

Start with buying that color wiring diagram and making a pot of coffee.

Hope the input helps.

John
 
I would highly recommend this:

1968 Chrysler Color Wiring Diagram - ClassicCarWiring

Spend the $30 and get the large one sided version.

An absolute must for chasing down electrical issues.

And for making sense of it all.

What's the history of the car? Untouched one owner, train wreck, lot's of creative electrical "engineering"?

My initial speculation would be a loose connection/switch, weak/lost ground, or chafed wire somewhere in the circuit.

The above could all be affected by the opening and closing of the driver's door.

Or even hitting a bump, shifting out of park, taking a turn, etc.

Make sure that all the parts of the instrument cluster are properly installed and tight, it is grounded to the dash frame.

I've had headlight switches do odd things before the internal circuit breaker finally failed.

This is probably unrelated, but something to file away for future reference:

I had the ammeter gauge fail in the black 2DHT. Before a complete loss of power, there were odd symptoms of a bigger issue. The fuel gauge would come and go, the headlight switch would trip repeatedly, super bright dash lights, rare starting issue, etc.

Once removed and tested, I discovered that one of the connecting posts had worked it's way loose enough to lose continuity. Over time, the connection separated. A light twist with pliers restored it.

I installed a known good ammeter and all was fine again.

Start with buying that color wiring diagram and making a pot of coffee.

Hope the input helps.

John

Thanks John. If this was just dash lights I would be thinking bad ground but with no tail lights unless I feed it 12 volts through the instrument lamp circuit I seem to be pointed to the switch, but the switch is not acting bad. I thought I verified the connector on the back of the headlamp switch. When I loose the lights, I always have headlights so its not the breaker. I'll spend the $30. Tx.

Dan
 
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