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Gauge cluster/Dome lights issue


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88 MJ, 6cyl.

 

All the bulbs are good in the blinkers, tail, etc.

 

When I pull the stalk to activate the running lights or headlights, on the cluster, the RIGHT TURN INDICATOR stays lit continuously. When I active the right blinker, the gauge cluster indicator light will blink on and off as well. The front and rear blinkers still work normally.

 

Also, my B pillar lights and kick panel lights will always stay on with the door open. The door-peg is not jammed shut. When I push the peg in (to simulate a closed door), the lights will dim but not go off.

 

Is it possible these two issues are related? Where do these lights ground at? Any common failure points?

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You lost a ground. Start with the right turn signal and probably right on the socket. The power back feeds through the other filament and uses a ground from another light or whatnot. Noting which lights are dim and under what condition can help locate the bad grounds.

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Alright, did some prelim. testing.

 

The passenger side b-pillar dome light is the one with the bad ground. I tested both of the 'constant' and 'switched' terminals and they both tested 12V. At least I've narrowed it down to one side of the truck.

 

As far as the socket. I replaced the bulb with two new ones and no dice. Tested the outlet and it only shows about 9.5V with the lights on. What would cause a low voltage?

 

The printout from Advance shows a suspect 11.18A drain on the system. Maybe this is partly the cause.

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Ha! I am with the Alpha-Guy and his (listed) problems.

 

I have the same dash problem :/

 

Ground huh :dunno:

 

What's up with your nicknames? :roll:

 

Can you have a ground that's kind of/almost bad? How do you manage a 3V drop in current?

 

Nicknames?

 

I haven't dug into my issue yet. I just have the same dash issue with the right turn signal lit when power is on. My dash lights don't illuminate either. :shake:

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Alpha-Boy, Alpha-Guy. One day, you'll run out of names to use. 8)

 

My dash lights work. Maybe yours is a headlight switch issue?

 

Alpha Guy wasn't me :D

 

I have a used switch to replace and find out. Keep your fingers crossed :wavey:

 

My MJ is FULL of electrical bugs. I placed a second fuse panel under the dash and started migrating things over as I address them. When I got the rig it was hammered $#!& with aluminum foil shoved in the fuse block and things half working. Making progress but I fear I may be months away from figuring out all my bugs.

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One of your cohorts, nontheless.

 

Let me know if your used switch helps any of your problems. I doubt that's my issue as it'd be too easy to fix.

 

There was some wacky $#!& going on in my fusebox, too. They used they tiny fuses in some slots, which melted some of the plastic.

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I narrowed down my electrical issues:

 

DOME LIGHT

1. Driver side B-pillar harness checks out ok.

2. Passenger side B-pillar harness shows ~12V with door open and closed on both of the blades on the connector (always on and door only).

 

Where does the wiring for that run? Down the B-pillar and through the cab?

 

 

GAUGE CLUSTER

1. I turned on the parking lights and the passenger side one did not come on (the one under the headlight).

2. Tested the socket and only found ~9.5V at the socket.

 

What could cause having a 3V drop from battery to the light? Bad ground?

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You need to be careful when using a voltmeter when finding faults. What are you measuring the voltage to? Are you getting 9.5 v from socket terminal to socket body or directly to battery or some know body ground? It will put the voltage loss on the other side of your probes.

You need to check the resistance of the socket body to the negative terminal of the battery. You can use either an ohm meter or a light bulb and the brightness will tell you alot. Now you are checking each component of the circuit rather than multiple components. For me it is just quicker and simpler without alot of thinking.

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You need to be careful when using a voltmeter when finding faults. What are you measuring the voltage to? Are you getting 9.5 v from socket terminal to socket body or directly to battery or some know body ground? It will put the voltage loss on the other side of your probes.

You need to check the resistance of the socket body to the negative terminal of the battery. You can use either an ohm meter or a light bulb and the brightness will tell you alot. Now you are checking each component of the circuit rather than multiple components. For me it is just quicker and simpler without alot of thinking.

 

At the time, I just checked the prongs inside of the socket body. I did this to ensure that voltage was even present inside the socket. This way I know that there's something present in the socket and that the socket works. I had a problem with the driver side not working at at, and it was a bad ground tab.

 

The next step is to check the resistance between:

1. Socket tabs and battery

2. Wiring (directly before the socket) and the battery

3. Wiring (directly before the socket) and the socket tabs

 

These steps will allow me to determine which part of the circuit is at fault and narrow it down to a more specific component. As I understand it, the resistance should be less than 1 ohm. Obviously, the lower the resistance, the better.

 

What would cause a loss of 3V from the battery to the socket? Excess resistance in the wiring? Bad ground? Poor connections?

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Well, that's just it. If you measured the 9.5 between the prongs and the socket body, the drop could be on the power side or the ground side. Imagine yourself an electron and you're traveling down the wire, go through the filament, and now you have a fork in the road. Hurry home like you should but there is obstruction (2.5V) in the way or take the detour of less resistance up through the instrument cluster and then home. Most of it will go the least resistance. If the voltage drop to ground (either path) is too high, there is not enough voltage(power) to make the like glow or all of the light on the path including detour glow dimly.

Your new steps look good. Worst comes to worst, you start pulling fuses and light bulbs to isolate circuits.

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Well, that's just it. If you measured the 9.5 between the prongs and the socket body, the drop could be on the power side or the ground side. Imagine yourself an electron and you're traveling down the wire, go through the filament, and now you have a fork in the road. Hurry home like you should but there is obstruction (2.5V) in the way or take the detour of less resistance up through the instrument cluster and then home. Most of it will go the least resistance. If the voltage drop to ground (either path) is too high, there is not enough voltage(power) to make the like glow or all of the light on the path including detour glow dimly.

Your new steps look good. Worst comes to worst, you start pulling fuses and light bulbs to isolate circuits.

 

So, what types of problems can cause a voltage drop of 2.5V? I'm gonna try to dig into this some today, barring rain.

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I can see that.

 

As previously mentioned, I have already replaced the driver side socket since the tab rusted out all the way. The passenger side did have some water in it after our last rain.

 

I'll double check the connections thoroughly and report back with the resistance values I get.

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Alright, did some more testing:

 

Tested the ground tab on the socket against the battery ground. Came up "OL" which indicates an open circuit.

 

I then tested the metal prong on the wire that goes into the socket against the battery ground and came up with .1ohms.

 

I then tested the bare wire (made a notch in the insulation) against the battery ground and it came up .1 ohm.

 

So it seems the socket needs replacing. What's the easiest way to do this?

 

When I replaced the other side, I didn't want to try to splice new wiring on, so I cut the socket off with a dremel. Talk about a major PITA.

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