Gauges stopped working

mark1978 · Post by **mark1978** » Sun Oct 22, 2006 10:44 am

Trying to get my gas and temp gauges working once again on a 70 d100 I aquired in a trade. I took apart the dash and found the capacitor thats grounded to the cluster was loose and tightened that down and they worked fine.
A week later I replaced the horn relay and went for a drive, the guages had stopped working again.

I have 12v coming into the gas gauge and sometimes have 12v coming out as well, my guess is the gas gaufe itself has a short. Have tried running new ground from the cluster to steering column, and from fuel tank to a clean body ground and this doesnt seem to work.

Any ideas? I`d prefer to keep the stock gauges rather than buying aftermarket.

Jeffc · Post by **Jeffc** » Sun Oct 22, 2006 11:56 am

below

Jeffc · Post by **Jeffc** » Sun Oct 22, 2006 11:58 am

If at any time you have 12v comming out of the fuel gauge (at the top post that runs to the temp gauge)
you have a problem> the limiter that is built into
the fuel gauge is bad> limiter should hold voltage
to a max of 6 volts (pulse of 0 to 6 volts).
Any more than 6 volts out of gauge will burn out
the gauge (both the fuel and temp), it may take
a few minutes or right away as the gauges will
peg before cooking.

No way around it, your looking for a new (good used) temp
and fuel gauge.
check this link
http://photos.imageevent.com/jeffc/tech ... 20test.JPG

sireland67 · Post by **sireland67** » Thu Oct 26, 2006 9:26 pm

Jeff,
Is the test the same for a 71 fuel gauge?
MY 71 fuel gauge has never worked and the temp gauge workes very intermitted.
I have seen the temp gauge work, shut the truck off to adjust something and start it back up, not moving the truck and have the gauge not work.
Thanks Shawn.

Jeffc · Post by **Jeffc** » Fri Oct 27, 2006 12:09 am

yes, same test all years 61 to 71 at least...

Russ · Post by **Russ** » Fri Oct 27, 2006 6:51 am

When you have a guage problem, an easy way to test the voltage regulator is to pull off the wire at the engine temp sender, Measure the voltage there and it should be about 6 - 7 volts. It won't be steady but will fluctuate from about one volt to 6 -7 volts. This is easier that trying to get under the dash. You can do the same thing with the wire to the gas guage but it is not as convenient as the temp wire.