5v sources on 1988 ranger?

[88xltranger]

I know that there is a resistor in the gauges that converts 12v to 5v, but is there any other places on the truck that gets 5v? Im having roughly 5v bleed into my turn signal wiring lighting up the rear LEDs dimly.

 

[Uncle Gump]

Most engine sensors use a 5 volt reference signal.

That said... I highly doubt your problem is a short to a 5volt reference signal.

LED lights can be tricky... they do goofy things.

 

[SenorNoob]

Could the turn or hazard relay some carbon build-up conducting a small current?

 

[rusty ol ranger]

Could the turn or hazard relay some carbon build-up conducting a small current?

Id be looking for a failed/corroded brake light switch or turn signal switch. Or bad ground for the turn/brake lights

 

[88xltranger]

I've checked or replaced everything I thought could be related including both hazard and flasher relays, light switch, multifunction switch and brake switch. I dont know where the ground for the rear lights terminates but I did cut the grounds out and grounded them individually for testing. Same results.
I did find that if I go under the hood and unplug the rear harness, all of the front lights will turn on. They are led also

The lights do function correctly otherwise so it isnt something that HAS to be fixed, its just something that bugs me.

 

[rusty ol ranger]

Electrical isnt my strong suit...but...maybe try putting a normal bulb back in and see what happens? Or did you change sockets to?

 

[88xltranger]

I'm usually pretty good with eletrical but this truck throws me off for some reason. I havent changed sockets but I've checked and they seem fine. I have new 3157 sockets but I havent put them in.
If anybody is well versed in electrical diagnostics, I did get a weird reading with my digital test light and power probe....the test light will read 5.8v for just a second and lights up red for power, it stays lit up but after a second the voltage doesnt register. Thats on the wires out to the tail lights

 

[88xltranger]

Most engine sensors use a 5 volt reference signal.

That said... I highly doubt your problem is a short to a 5volt reference signal.

LED lights can be tricky... they do goofy things.

Im not saying its a short to 5v, but I'm thinking a 5v signal is somehow making its way through the lights. Maybe they are acting as a ground path. Im not sure.

 

[Uncle Gump]

Im not saying its a short to 5v, but I'm thinking a 5v signal is somehow making its way through the lights. Maybe they are acting as a ground path. Im not sure.

Sneak path

I've stayed away from all the LED conversions... many cause issues. So I'm not so versed in offering a solution to you. Many on here have converted... and there is usually a problem. Try a search on TRS.

 

[RonD]

If you are reading 5v on a light bulb wire then its a partial or corroded 12volt connection most likely

If you have the voltage Key Off then it can't be from cluster

 

[88xltranger]

Sneak path

I've stayed away from all the LED conversions... many cause issues. So I'm not so versed in offering a solution to you. Many on here have converted... and there is usually a problem. Try a search on TRS.

I've never had a problem personally with them aside from this truck. From searches I havent found a similar issue.

 

[88xltranger]

If you are reading 5v on a light bulb wire then its a partial or corroded 12volt connection most likely

If you have the voltage Key Off then it can't be from cluster

The voltage only appears with key on. It appears on the turn signal/hazard side. The lights function completely normally. They dim and brighten up with brakes and all signals work as they should with 12v. Its just rather annoying to see them dimly lit up everytime I turn the key switch on.

 

[RonD]

Which lights are dimly lit?

All or just dash turn bulbs?
Or rear or front

Brake lights, 4-way and headlight/park lights have 12volts all the time

Front and rear turn signal bulbs are on separate wires
And left and right as well, so there are 4 wires

Dash turn and front turn share a wire, but left and right so 2 wires
So a short in dash should only light up dash and front bulbs on ONE SIDE

The turn signal stalk, multi-function switch, is the only thing in common to all 4 wires
When its in the "neutral" position all 4 wires are disconnected from each other, there are 4 separate switches inside the turn signal stalk, one for each wire

So a short to one of the 4 wires should only effect bulb(s) on that one wire, its not connected to the other 3 wires

diagram here: https://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_turn_stop_hazard.JPG

You could pull fuses with Key ON to see which one turns off the lights, that may help in tracking down the issue

Google: 1988 Ford Ranger fuse box diagram

Should find one that matches yours

 

[rusty ol ranger]

Which lights are dimly lit?

All or just dash turn bulbs?
Or rear or front

Brake lights and headlight/park lights have 12volts all the time

Front and rear turn signal bulbs are on separate wires
And left and right as well, so there are 4 wires

Dash turn and front turn share a wire, but left and right
So a short in dash should only light up dash and front bulbs on ONE SIDE

The turn signal stalk, multi-function switch, is the only thing in common to all 4 wires
When its in the "neutral" position all 4 wires are disconnected from each other, there are 4 separate switches inside the turn signal stalk, one for each wire

So a short to one of the 4 wires should only effect bulb(s) on that one wire, its not connected to the other 3 wires

diagram here: https://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_turn_stop_hazard.JPG

He has spoken.

 

[88xltranger]

Which lights are dimly lit?

All or just dash turn bulbs?
Or rear or front

Brake lights, 4-way and headlight/park lights have 12volts all the time

Front and rear turn signal bulbs are on separate wires
And left and right as well, so there are 4 wires

Dash turn and front turn share a wire, but left and right so 2 wires
So a short in dash should only light up dash and front bulbs on ONE SIDE

The turn signal stalk, multi-function switch, is the only thing in common to all 4 wires
When its in the "neutral" position all 4 wires are disconnected from each other, there are 4 separate switches inside the turn signal stalk, one for each wire

So a short to one of the 4 wires should only effect bulb(s) on that one wire, its not connected to the other 3 wires

diagram here: https://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_turn_stop_hazard.JPG

You could pull fuses with Key ON to see which one turns off the lights, that may help in tracking down the issue

Google: 1988 Ford Ranger fuse box diagram

Should find one that matches yours

Dash bulbs are still incandescent, havent checked voltage at them but I have leds coming for them which should be here today. Only place i have 5v is on the signal side of the rear lights.
I have a good diagram of the entire truck.
I have already tried pulling all fuses and they never went out.
Only time they went out was when I unplugged the rear harness from under the hood, but at the point all of the front exterior lights lit up dimly.
I will post the diagrams i am working off of.