Dash lights backwards-working suddenly...

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DrillNFill

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Hi, I've had a strange lighting problem since having my interior done a few weeks ago. 1970 Dart swinger Slant-6. I'm not a good mechanic when it comes to electrical stuff, so if we can shed any light on the issue I will pass it on to my trusted old-school mechanic!

Two weeks ago i had the seat covers replaced with Legendary original-style covers (which look awesome by the way). I had a local interior guy with decades of experience do this who has worked on my cars before. he was also supposed to install my new dash pad- i knew its a pain so i asked him to do it. He agreed initially but after he started removing parts of the dash, he decided against it because he "didnt want to mess anything up for me". I understood and was fine with it, everything worked fine driving it home- in the daytime.

On friday, i took the Dart to a cruise that lasted past sundown. when i switched on the headlights to go home, my dashboard turn signals and little red "hi-beam" indicator stayed on constant, the speedometer lights were dark, and my fuel gage and temp gauges on the left side imeadiately went dead. my lights and gauges normally work fine. Using the left and right turn signals, i noticed that when the outside light blinked ON, the dash light went OFF, and vice-versa. same thing with the high-beams. they seemed to do the opposite of normal, and everything on the outside worked as normal. Only the dash lights/ gauges were effected. When i shut the headlights off again, everything went back to normal (gauges worked again, turn signals/ beam indicator worked in the normal fashion).

what could have caused this all of a sudden? i do not know what the interior specialist did or didnt touch. could it be something was reinstalled backwards on the headlight switch? my dashboard type is shown below.

Anyone have any ideas? thanks in advance!
Dart dashboard .jpg
 
I don't know but check your grounds. There is one under your steering column that he may have removed that's on the steering column bracket. I've seen bad or no grounds make electrical go all wonky. I had a truck that did all kinds of **** until I found a broken battery to body ground wire.
 
This certainly sounds like a grounding problem. The cluster is poorly grounded by the mounting bolts to the dash frame, and the PC board is grounded to that by it's mounting screws. Find a common ground on the PC board and install a pigtail, then bolt the pigtail to either the column support or the dash frame
 

Why the button screwed to the dash. Looks to be previous electrical problems , Starter or horn with a quick fix?
previous owner's idea of a quick horn fix due to non-working rim-blow steering wheel :) i have a new original-style wheel setup to go in the near future
 
I don't know but check your grounds. There is one under your steering column that he may have removed that's on the steering column bracket. I've seen bad or no grounds make electrical go all wonky. I had a truck that did all kinds of **** until I found a broken battery to body ground wire.

This certainly sounds like a grounding problem. The cluster is poorly grounded by the mounting bolts to the dash frame, and the PC board is grounded to that by it's mounting screws. Find a common ground on the PC board and install a pigtail, then bolt the pigtail to either the column support or the dash frame
I know what you guys are saying, but I just thought it was weird that everything worked perfectly normal with the headlight switch shut off. Thats why my initial thought was something was reattached backwards with the switch. Would the dash gauges/ lights still work normal in the daytime with a grounding issue?

and thank you all i appreciate the help! Most everyone here has more experience with these older cars than I :)
 
Headlight circuit needing a good ground may be pulling it from other sources when on.
 
Headlight circuit needing a good ground may be pulling it from other sources when on.
Doubt that frankly. Headlights are grounded up front on the rad support. I'd bet the trouble is right in the cluster area
 
Hi folks, just an update and another question, the original problem has been figured out- there was a plug on the back of the cluster that was reinstalled improperly so some of the pins were bent and had to be repaired.
So that part is resolved, but now another issue has cropped up, both the fuel gauge and the temp gauge are non-functional, when they were working before. I know from reading the forums that this is fairly common but I cant recall what the issue usually is. My mechanic thinks the issue is the voltage reducer behind the instrument cluster (pictured below) which i will order today, but are there any other common culprits for this issue that should also order just in case?

Again, thanks everyone for your thoughts and experience!
Screenshot 2024-10-24 095753.jpg
 
I would NOT install an original type IVR. Look up RTE and there is or was a couple / three others


Some things you need to do while you have the cluster out

1...provide a ground pigtail to a ground spot on the board (the board mounting screws some of them are ground)

2...Clean and solder jumpers from the springy contacts in the board for the limiter, to the PC board traces

3...Clean the board where the gauge studs go through and make contact. Just tighten/ loosen/ tighten the stud nuts a few times to "scrub" the board

4..Clean the area where the lamp sockets make contact with the board, bend the lamp socket contacts appropriately for better contact, and inspect them for looseness and corrosion. Change the lamps and make certain the socket is clean.

5...Inspect all the PC board harness connecting pins for looseness where they meet the board. clean, flux and solder them at the base, to the board traces.

6 Examine the ammeter for heat damage, as well as the eyelet ends where the big black and big red connect.

Do you have a service manual? If not, run over to MyMopar.com and download one, free. You may have to accept Dodge vs Plymouth, etc etc for some years.
 
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I would NOT install an original type IVR. Look up RTE and there is or was a couple / three others

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Some things you need to do while you have the cluster out

1...provide a ground pigtail to a ground spot on the board (the board mounting screws some of them are ground)

2...Clean and solder jumpers from the springy contacts in the board for the limiter, to the PC board traces

3...Clean the board where the gauge studs go through and make contact. Just tighten/ loosen/ tighten the stud nuts a few times to "scrub" the board

4..Clean the area where the lamp sockets make contact with the board, bend the lamp socket contacts appropriately for better contact, and inspect them for looseness and corrosion. Change the lamps and make certain the socket is clean.

5...Inspect all the PC board harness connecting pins for looseness where they meet the board. clean, flux and solder them at the base, to the board traces.

6 Examine the ammeter for heat damage, as well as the eyelet ends where the big black and big red connect.

Do you have a service manual? If not, run over to MyMopar.com and download one, free. You may have to accept Dodge vs Plymouth, etc etc for some years.
thank you sir! And yes i do have a factory Service Manual its come in handy over the years, whereas the Haynes manual is kinda...not very helpful =)

I will pass on your circuit board maintenance points to my mechanic- im over my head dealing with 54-year old electrical circuits but he's got 40 years under his belt!
 
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