Ok I've got a strange problem I've been trying to figure out for a few weeks and I'll start from the beginning.

Bought truck a few months ago with almost no electrical working, drove home with one fuse working. Fuse box rotted out.

Majority of time spent over the last few months have been spent rewiring and replacing electrical components and wires.

Most systems back up and running but lighting circuits have continue to give me all kinds of black magic.

Replaced all exterior lighting cables, sockets, housings, bulbs, master switch, high beam switch, turn signal switch, circuit board on gauge cluster, door jamb switches, door jam sockets, cab lights, cab light wires, brake light switch, fuse panel, all interior bulbs. Probably a few others I'm forgetting.

Today I finished wiring up all of the exterior lighting and where it goes to in the cab, the high beam switch socket, column switch socket and light switch socket I left 6" pigtails on to terminate to the new wiring. Copper was still shiny on the OG sockets except the floor plug which was a little blacker than I would like but not fully gone. Will try and order new sockets soon.

I have not replaced the voltage regulator on the board yet as this was the only unavailable piece at the time I rebuilt some of the cluster, one has become available and is on its way. The gauges are all original, I bench tested them on a variable DC power supply and all appeared to work correctly.

Before rewiring all exterior lighting it was not working correctly, drivers side taillight significantly dimmer than passenger, blinkers would not work with headlights on, front turn lamps would work in and out, dome light would stick on and the master light switch would throw sparks when either turning the dimmer left or right but more significantly to the left. Almost guarantied pop of sparks when clicking all the way to engage the dome light. Eventually if I mess with the dimmer enough if will pop a 3AMP fuse tied to the circuit board. It seems like when the shaft in the center of the switch makes contact to ground is when it throws sparks. This is my second new switch.

After rewiring all the exterior lights they all work 100% correctly now without error in all positions but the master switch still likes to throw sparks at me when adjusting the dimness, a lot less not but its still there.

Another potentially related issue if the original water temp sending unit wire was burned in several spots when I bought the truck. I repaired the burnt parts I could see and failed to move the gauge. I replaced the sending unit and now the gauge works but maxes out as soon as the key is turned even if the engine is cold.

Things I have not replaced in the cab are dome light housing, dome light wiring, seat belt warning wiring, seat belt warning buzzer, wiper switch, wiper socket, wiper motor, light switch socket (One of the few parts that don't appear to be reproduced) High beam socket, Column socket, circuit board socket, heater wiring or core, Heater control unit, fan speed socket, fuel tank selector switch and socket. All of these things appear to work fine.

I know thats a lot to read but if you have had this problem your help is appreciated. My neighbor claims he had the same problem once and was never able to figure it out.

 

Ok I have never seen a head light switch throw sparks.
Is the switch installed or you have it out for the re-wiring?
If out I think I would install it and see what happens.

NOW! This sounds like a ground issue to me.
I would go over ALL grounds and maybe add some.
From battery to motor> motor to frame.
Motor to fire wall for the cab ground 10 ga wire should work.
Dont trust the battery to fender ground that some battery cables have to ground the cab.

Do not forget the motor to frame and motor to firewall.
You may want to add frame to bed as the bed bolts are pretty old and some beds are set on rubber pads so bed may not be grounded good.
Good grounds will fix 90% of electrical issues.
If you have all them grounds pull them and clean and see what happens.

On the temp gauge if you remove the wire from sender dose the gauge still peg or not move?
If not move then I would say the sender is bad or for a light not a gauge.
Test it with an ohm meter if it is closed then bad or light sender.
Dave ----

 

Oh install a head light relay kit.
This takes all the power off the switch so all the switch is doing is turning on / off the relays, power is coming from the battery.
It will also make the head lights brighter as they will now get full 12 volt power.

You can get the kit thru LMC, think DC, JBGY, Ebay and Amazon I got mine from LMC years ago for a different project but being it is n=on hold is used on my 81 F100.
Dave ----

 

I had a crazy thought this morning, the cabling all appears to be good now and the socket appears to in decent shape. 2nd new master switch being bad would be like wining the idiot lottery...which I've actually won a few times this year alone.

The chassis of the master switch in theory is to be grounded the dash, sandwiched by the nut, makes sense to me. Maybe whats going on here is that either the nut isn't seating properly in the switch itself either due to a warped dash, nut, switch or arm? and its acting in a similar fashion to when you take the negative cable off the battery and sometimes it throws spark?

The switch doesn't constantly throw sparks, if messing with it I can't rotate freely sometimes without anything happening, I'm thinking maybe things are just bending and flexing enough for it to lose contact?

When I put the power probe to the chassis of the switch last night I read solid ground and I don't recall it throwing sparks when touching with the probe, which would make sense as its keeping its path to ground through the probe?

Just speculating...

 

The switch when rotating is a "potentiometer". So as your turning it's making new contact. If that part of the switch is only used infrequently it will corode over time and when you use it again it will struggle to connect because the corrosion. Contact cleaner is your friend here. Until the contact is clean , eventually that happens by just working it, it will show it's struggles to find connection by sparking. If you want grab one at the junkyard and take it apart. You'll know everything there is to know about with the schematic. When you decide to go relay, I found some really trick waterproof relay boxes that are really high quality and inexpensive that gives you a real finished look when your done. They're realitively in expensive. I've got pics just need to dig them out. I've been rather sloppy keeping up with my archive. Switched computers to many times. I'm working on a server tower to adequately house and control the stacks, watch out for AI,(artificial intelligence), the stacks with the ability to back it all up.
Anyways , good luck with the project. Post back with any progress or questions and keep your wits about you :-)

 

I had a long winded answer for the headlight switch. The internet ate it. Short version is the dimmer resistance element is a coil of nichrome wire. It’s loose and is touching something it shouldn’t. Only viable fix is replacement.

michael

 

Sorry to tell you this, but it's not only possible, it's actually quite common these days. Used to be able to trust new parts for what they were. Now you have to be completely skeptical to the point of buying different brands, or even from different sources.
There are stories here of members buying three, four, or even five bad/defective parts in a row before finding a good one. Alternators, starters, starter relay/solenoids (the worst offender!) and, yes, switches.
Ignition switches, light switches, wire connectors and pigtails. You name it, we've heard of them being defective right out of the box.
Sometimes they fail in short order, sometimes they're bad right out of the box. And that's not counting the times that the parts aren't even the right ones in the box!

So no, it's not out of the realm of possibility that you have two bad parts.
Doing the same thing? Less likely, but not impossible. Were these both new switches by any chance? Or was one the original and the second a replacement?
Good light switches do not throw sparks. Something is shorted internally.
Bad grounds do not cause this. A light switch simply closes contacts to connect power to load. It's not even usually polarity sensitive in our older models. This is a short-to-ground problem and is not caused by a lack of them.
We can always benefit from more grounds, especially for the body and dash areas, but I don't think it's your existing problem.

Don't ever assume a new part is good until it proves it to you. Which is why you can't just fix a problem by throwing parts at it anymore. You may very well add a secondary problem by installing a new part.

Paul

 

 

Could very well be another bad switch, I'm not ruling it out. I received 3 bad brake boosters this year, bad aux relay, bad ignition coil. and a starter motor that crapped out in two weeks.

Dad's a 30 year Dodge mechanic and says worst 2023 is the worst manufacured auto parts year ever, guys at the supply house and local mechanics been saying the same thing.

Its the second new switch. The switch that came with the truck was shot, put in a new one and seemed to work for a few months before throwing sparks, swapped for a replacement and same deal.

 

Made sure the switch was really guten tight, still throwing sparks. Was able to pick up new switch they shipped in today but I put the truck up in storage so won't be able to test probably for a few days.

 

Crossing fingers that the third time’s a charm. 😁

 

In the mean time, has anyone ever taken the time to take a meter to the socket?

I had it unplugged from the switch the other day and was reading good voltage on the contacts with my power probe on the socket end. Didn't have time to meter with the switch on and mess with the switch positions.

 

You don’t have a short at the socket itself. If you did, you’d have sparks even with it disconnected from the switch.
Something inside the switch, or something in one of the wire terminals or wires is causing the problem.
Or at the other end of one of the wires too of course.
Presumably you verified that all running lights, brake lights, headlights, and anything else that’s connected to the headlight switch, is not shorting out?

Did you say you have a Power Probe? If so, you can easily test your socket, and its individual circuits for a problem.
you can test the switch itself with an ohm-meter I would think.
If something is connected to something else, that’s not supposed to be connected, there’s your problem! :-)🙄😉

 

Thats why I was curious if somebody knew what readings on what terminals are on the socket itself and with the switch in different positions. ALL of the exterior lights on the truck work correctly NOW after rewiring all the EXTERIOR circuits. I have not gone through the internal lighting circuits like the dome light wiring, or connection to cluster. Inside the truck as far as lighting goes I only have the dome, the cluster, the wiper/light switch backlight, and lighting for the HVAC controls. No glove box light, ashtray light, aftermarket gauge lights aren't connected yet, courtesy lights, etc.

Only lighting related things I replaced other than the bulbs were the door switches and their sockets.

Before I rewired the exterior lighting the dome light was sticking on but that has stopped now.

The interior lights all work as well, I replaced every bulb in the cab minus the one in the column and all work. They even dim like they should when this switch is throwing sparks.

I have been combed through the wiring harness in the cab several times and I only discovered one nick in one of the ignition wires...probably from the factory, that I did fix.

Since the cluster is tied into the system I'm also not gonna rule out that the voltage regulator on it may be wonky or possibly the new circuit board I installed could be bad as well or maybe they sent me the wrong one.

 

For dome light give this a read, It's covered in that thread with thorough explanations.