Did I just burn out my voltage limiter in the instrument panel?

[Kern Dog]

I fixed it!



I feel like a Big Boy.

Actually, I didn’t do a dang thing. I went out to move the car into the shop and the gauges worked. Well, the tach is still lazy but it may be something inside the tach itself that is messed up.
I put three gallons in to see if the gas gauge needle would move up. It did. I warmed it up to see if the temp needle moved. It did too.
I’m not sure why. The battery voltage was low and I did charge it up but I did nothing else.
Kern Dog luck is something I am grateful to have. I can fall off roofs and live, I must be charmed.

 

[Kern Dog]

Who has tested one of these to know if they are good ?

I’m going to start up the 67 Dart next.
That one has a repro fuel sender that did work awhile back but has shown E for awhile. Maybe because the car sits so long, the gauge never expects me to put gas in it?
I have a spare panel for parts or to swap in….

Yeah… it has “storage dust” on it…



It isn’t perfect…

I’ve soldered wires together so I guess I can try soldering a pin on. What do I have to lose?

 

[dadsbee]

Put 12 volts on it,,, + on ignition, ground on outer tab. Get an old voltmeter with a sweep needle. Meter leads on ground and the third pin to the right in the picture. It should cycle on and off with a high of 5 volts.

 

[Kern Dog]

The Dart instrument panel pin seemed like a relatively easy fix. I have several 72-76 clusters and from other cars too.

It turns out the Dart used longer pins than the other stuff.

Guess who saved the day ?

The original panel from Jigsaw….

 

[Kern Dog]

The printed board only had two pins left on it so I wasn’t cannibalizing a perfect part.

It was barely soldered in. It dang near pulled right out like teeth on a homeless guy.

These look the same diameter as the ones in the Dart cluster. They are hollow. I don’t know why. Cost savings?

I’ve never done this before but given my curious nature, I gave it a try.
The pin has a slight flare where it seats in the circuit board. On both sides it measured .094” or thereabouts.

I found a matching drill bit…

Easy so far…

It fit in a bit snug.

A short soldering session….

It is in and passes the “no wiggle” test. I’ll coat the pins with dielectric grease.

I now have a spare panel here in case the one in the Dart now is messed up.

 

[Kern Dog]

Put 12 volts on it,,, + on ignition, ground on outer tab. Get an old voltmeter with a sweep needle. Meter leads on ground and the third pin to the right in the picture. It should cycle on and off with a high of 5 volts.

The third pin from the right leads to the center spade on the voltage limiter.

The center spade shares space with the black wire leading to the condenser/suppressor.

For me, my mind goes blank when it comes to understanding some of this electrical stuff. It might as well be in Chinese for all I can make sense of it.
I changed the limiter in the existing panel and it made no difference.
I changed to the panel with the repaired pin. No change. I grounded the fuel sender wire, turned the key ON and still no movement. I put a test light on the temp gauge wire and got no light.
I know that it is rare to have two bad parts in a row. Having two instrument panels both with dead temp and fuel gauges can’t be common.
The wife has heard me over the years…. Working within my limited electrical skills and often scratching my head in frustration… She asked if I could mock up a functional panel from another car using some manner of hybrid wiring. Yeah… I’ve done that. My tilt wheel steering column project ( On hold for the time being) required me to make an adapter harness to join two different sets of wires together.

 

[Don Frelier]

Put 12 volts on it,,, + on ignition, ground on outer tab. Get an old voltmeter with a sweep needle. Meter leads on ground and the third pin to the right in the picture. It should cycle on and off with a high of 5 volts.

It doesn't drop the voltage just opens and closes periodically.
So you'll see 12V then nothing. It will stay on longer initially since it operates on a heated winding and expands a bimettalic arm.
After it warms up I think it's on something like 4 out of 10 seconds.
The gauges have a ton of averaging built in to accomodate the pulsing voltage.

 

[Kern Dog]

I tested the panel that was in the car by momentarily putting 12 volts to the terminals on the back…

First the fuel gauge….

Then the temp…

The limiter was out.

I’m happy that I did get some reaction.
This at least tells me that the gauges DO work so that leaves the wiring…
The car does sit outside and rodents have been known to chew the wiring in cars. Usually it is the late model stuff, some blame the soy based insulation used in newer cars. The Wife’s Honda has had a few wires replaced due to rodents.
The Dart often has rat turds under the hood and empty nut shell piles that I have to clean out. I’ll look at the wiring next.

 

[dadsbee]

It doesn't drop the voltage just opens and closes periodically.
So you'll see 12V then nothing. It will stay on longer initially since it operates on a heated winding and expands a bimettalic arm.
After it warms up I think it's on something like 4 out of 10 seconds.
The gauges have a ton of averaging built in to accomodate the pulsing voltage.

Yep brain fart while multitasking and little sleep this week. 12 on and off, and averaging 5 volts in the gauge movements.

 

[Don Frelier]

An old 6 volt battery would have worked nicely.

 

[Kern Dog]

Yeah…. If I had one.
Mopar Action had an article years back…Ehrenberg had two AA batteries in series he used to test gauges.
I can’t find any damaged wires. I pulled the bulkhead plugs and cleaned them with DeOxit and a wire brush. They got blown out and filled with dielectric grease.
No change. I hate to be the guy that hangs aftermarket gauges below the dash because he can’t fix the stock ones.
I already have an oil pressure gauge there. That is the most important but it would be great to have these other gauges working.

 

[DeltaV]

It dang near pulled right out like teeth on a homeless guy.

 

[Kern Dog]

Just to close the book on this...
With the Dart, I unscrewed the speed nuts holding the circuit board to the housing and cleaned the contacts. I tested a few limiters and they all worked so I put one in the instrument panel that WAS in the car and put it back in. On a hunch, I pulled the fuel sender and found a rip in the float. With everything back together, the gauges work now.