Electric problems

[BE_Fury]

I have problems with electronics in my 71 Plymouth Fury III. The turn signal indicators are shines continuously. The fuel gauge doesn't work.
Today I also took the dashboard apart. I noticed a cable that made me suspicious. The Fury was once retrofitted with hidden lights. But these were then dismantled again.
The Fury is currently with the original front and lighting.

Do you need different wiring for the hidden lights?

I found this cable.

 

[BE_Fury]

I’ve found, that the relay is a „fuel level warning relay“

MoPar PN 2983828 - 3879514 low fuel level warning relay for 1970-73 Plymouth and Dodge E-Body

MoPar PN 2983828 - 3879514 low fuel level warning relay for 1970-73 Plymouth and Dodge E-Body

www.moparmall.com

Where can I get a new one?

 

[CBODY67]

What are "hidden lights"? What did their wires attach to in your harness? Have you downloaded a FSM from www.mymopar.com? Looked at the wiring schematics in it?

In the schematic, look for "common feed" circuits ("Common" does not mean "ground"), where one circuit is the feed for several functions, where those feed circuits are attached to items with "variable grounds" (for gauges and such). If the turn signal indicators are always "on", with the light switch "off", it could well be that a "ground" is not where it needs to be, so the electricity has found the easiest place it can "get to ground" for a complete circuit.

The fuel sending unit grounds to the fuel tank line with a special clamp at the tank, which touches the fuel sender itself and the fuel line coming from the tank and going to the fuel pump. Check that before buying anything! The FSM should have a picture of it, too.

Just some thoughts,
CBODY67

 

[65sporty]

What are "hidden lights"? What did their wires attach to in your harness? Have you downloaded a FSM from www.mymopar.com? Looked at the wiring schematics in it?

I am assuming he meant it had a different grill with headlight doors or hide away headlights. I don't know the Mopar exact name. 71 Sport Fury had them along with other models

 

[BE_Fury]

I found out that the cable connects the fuel warning relay and the lighting. So it has nothing to do with the hidden lights.

I will send the relay to a friend who will check and repair such parts. Can the flashing indicators indicate that the relay is defective?

 

[Big_John]

I found out that the cable connects the fuel warning relay and the lighting. So it has nothing to do with the hidden lights.

I will send the relay to a friend who will check and repair such parts. Can the flashing indicators indicate that the relay is defective?

The low fuel relay would have nothing to do with flashing indicators.

Inside it, there is the voltage limiter for the fuel gauge and the relay that lights the low fuel warning. It's an expensive piece to find as it was used in some E-Bodies and a bit rare.

The coil in the right side is the limiter and the left side is the relay.

 

[Big_John]

The turn signal indicators are shines continuously.

This could be a couple things. First and easiest is the flasher. There are two flashers, one is for the emergency flashers and one is for the turn signals. Just switch them and see what happens. The other piece that could have failed is the turn signal switch inside the steering column. That's checked with a test light and the service manual.

The thing to ask is if all the light bulbs, meaning the front turn signal/parking lights and the rear turn signal/stop/tail lights are plugged in and good. The flasher won't work without them in place. Any chance you converted those bulbs to LEDs? That will cause an issue like this too if you don't have the right flasher.

The fuel gauge doesn't work.

That could be the voltage limiter in the low fuel relay, but it's usually the sender in the tank.

Because you've taken things apart, it's very hard to help you figure this out. Electrical issues need to be looked at with everything in place before randomly pulling things apart. The best thing you could do now is put it all back together and do some really simple tests that can figure this out. If you want to just load up the parts cannon and fire it at the car, its your money. but chances of fixing the problem go down and frustration goes up as you tear apart and replace without direction.

If you decide to put it back together, here's a flow chart for finding the fault in the gas gauge. Gas Gauge Sender Flow Chart

 

[BE_Fury]

Thank you very much for your message and support!

This could be a couple things. First and easiest is the flasher. There are two flashers, one is for the emergency flashers and one is for the turn signals.

Just switch them and see what happens.

I swapped the turn signal relay. there has been no change.
I inserted two new relays. the problem still exists.

The other piece that could have failed is the turn signal switch inside the steering column. That's checked with a test light and the service manual.

I replaced the turn signal switch in the steering column with a new turn signal switch from my reserve. there was no change.

The thing to ask is if all the light bulbs, meaning the front turn signal/parking lights and the rear turn signal/stop/tail lights are plugged in and good. The flasher won't work without them in place. Any chance you converted those bulbs to LEDs? That will cause an issue like this too if you don't have the right flasher.

I checked all the light bulbs. the front turn signal/parking lights and the rear turn signal/stop/tail lights are plugged in and good.

I hadn´t converted the bulbs to LEDs. It is all original.

That could be the voltage limiter in the low fuel relay, but it's usually the sender in the tank.

I replaced the fuel sender unit with a new one. The old one no longer passed on a signal. the dimensions were always zero.
A ground clamp was installed because the old one was missing.
The fuel gauge goes off when I add plus. The cable from the fuel sender to the display transmits power.

Because you've taken things apart, it's very hard to help you figure this out. Electrical issues need to be looked at with everything in place before randomly pulling things apart. The best thing you could do now is put it all back together and do some really simple tests that can figure this out. If you want to just load up the parts cannon and fire it at the car, its your money. but chances of fixing the problem go down and frustration goes up as you tear apart and replace without direction.

If you decide to put it back together, here's a flow chart for finding the fault in the gas gauge. Gas Gauge Sender Flow Chart

I´ve put it all back together.


I'll check the lines. In the past I have repeatedly found jumpers that the previous owner installed.