Dash Gauge Failure

[Copper]

I performed the infamous amp gauge bipass in a 77' club cab.

Now my gauges don't work. They did work for a while, but died on the road. I must have worked something loose when I was digging around in the dash.

I've looked, and looked. I checked all the wires. Checked the fuses. Cleaned all the connections. Since none of them are working, I'd hesitate to blame it on the sending units.

I thought they grounded at the sending unit and received power from the dash, or is it the other way around? I'm guessing the instrument panel grounds when screwed into the dash? Is there a common power wire?

It's got to be something simple.

Any ideas?

Thanks a bunch.

[DODGEBOYS]

email me for the wiring diagrams


dodgeboysnet@hotmail.com

[WARLOCK76]

If ALL gauges quit, you have to suspect the power supply. You can make one from Radio Shack parts ($2) or I saw a new one on ebay yesterday for $20. It looks like a little tin box around the center of the gauge circuit board. Maybe you just pulled one of the wires off-they slide on spade connectors. Let us know what you find.

[Copper]

If it helps with any theories... The first time I noticed the gas gauge wasn't working, I tapped on it with my finger and it came back on. It wasn't until my next trip out that they failed to work at all. I've been unable to get them to come back with any amount of tapping, wiggling, or plugging and unplugging.

I'm sorting through the wires, one by one with a multimeter. I haven't found any bad ones. More to go. I can only tolerate hanging under the dash so long.

There is a short in the dash somewhere, but I can't find it. I'm guessing the two are related. Apparently, not enough to make a fuse blow, but bad (.7v). It could be under some tape. The truck still runs fine. I'm still looking. I'd like to eliminate the short before I start putting in good parts. Would a bad power supply on the instrument panel cause it? I'll have to pull it and check the draw.

I also found out, I have no instrument lights. Do they go through the power supply? I'm guessing it's a transformer? Metal with three blades - one looks almost like a bracket and goes around the outside and unplugs from the back - somewhat like an ice cube shaped turn signal flasher?

Don't they have the power supply at the parts store? Is there a test?

I'm sure some of the answers are in the wiring diagrams (Thanks Dodge Boys). I just need to study them some more.

All it takes is time ... and money.

Why is it I like these old trucks again?

[WARLOCK76]

The power supply is in the center. It's the little box.
Without this, none of the gauges work.

[WARLOCK76]

Here is an article about replacing the power supply with solid state pieces.

http://1962to1965mopar.ornocar.org/m...gulator64.html

[DODGEBOYS]

that part he,s talking about is a voltage limiter / it drops the voltage from 12v down to 5v / so if you have 12v go,in in you should have 5v com,in out / if you dont then its bad

[712edf]

Why is it I like these old trucks again?

Maybe because you aren't paying hundreds of dollars a month in payments, insurance, etc.....You won't be making those same payments 4-5-6 years from now, nor do you have to take it to some "technician" to get it fixed. When you get this bug fixed, they're will be a sense of satisfaction that doesn't come with writng a check. Good luck!
Bucky

[n1265]

check the " instrument cluster ground " wire ( pg 2 of the wiring diagram ) it comes from pin D on the " printed circuit board connector ". It is white 18 ga. wire with a black stripe. Mine is located on the left side of the cluster just above the headlight switch...

[Copper]

Never did understand those guys who try and get me to spend 500.00 or more a month, so I can save a 100.00 in gas.

It's nice to open the hood and see little more than an engine.

Thanks for the advice, that should get me on the right track.

[KRB64]

Maybe because you aren't paying hundreds of dollars a month in payments, insurance, etc.....You won't be making those same payments 4-5-6 years from now, nor do you have to take it to some "technician" to get it fixed. When you get this bug fixed, they're will be a sense of satisfaction that doesn't come with writng a check. Good luck!
Bucky

Amen brother!

[74w300uteline]

copper

I'm in a parking lot , dead battery in my VW rabbit, holding jumper cables asking for a jump start. guy pulls up in a new luxury import all proud and cocky. pops his hood to give me a jump, but all we can see is a giant plastic engine cover. we started laughing because i asked if he was sure that there was a motor in there.

[n1265]

And to think, I remember laughing at VW rabbits because of the motor that was in there...

[74w300uteline]

n1265

my brother inlaw refuses to ride in the rabbit. he calls it a "hamsterball with a sewing machine engine".