I just bought a samurai and on the way home I noticed the fuel gauge is stuck all the way on full, and the temp gauge is hasn't moved at all. It has a tac dash and its an 87' with the 1.6 engine swap with the trail tough wiring harness. Anyone have a fix? Thank you for your time.

I hope you're like electrickery - because - this is where you get to tracing the wires, and the fact that it's an engine conversion doesn't make life any easier.

As far as I know, those are two different circuits, and the only thing common to both is that they feed from the ignition ...

For the fuel gauge, power goes from the switch, through a fuse, through the gauge, to the tank sender and then to the chassis ground - if the gauge is stuck on full the problem is most likely a short circuit somewhere between the gauge and the sender (the wire is making contact with the chassis) or a defective sender.

For the temp gauge, power goes from the switch, through a duse, through the gauge, to the temp sender on the engine - if the gauge never moves from cold, you're looking at possibly no power to the gauge, a defective gauge, a broken wire between the gauge and the sender or a defective sender.

I'm not going to even guess at wire colors - who knows what's been changed?

Ack's FAQ should have the diagrams for the original wiring - I guess that's the best starting point.

Good luck.

Use a magnet to bring it back. It will work if the needle is made of magnet. If the needle is made of some other material then try tapping it gently. it may work.

Go to the root of most electrical issues on these trucks, check your grounds,
in this case the ground to the engine from the battery and battery to the
body, tight and bright (clean) and see if the gremlin goes away

Wild

X2 on the grounds. both read a reference against resistance to ground.

thanks guys for the help I have narrowed it down to a short I think. I started it up this morning and it worked, turned it off and then started it up later and its not working again. so its either shorting out or a bad ground.

Hey, This happened to my 87 Sammy TOO.

Do check all the obvious  electricals!
 
But Mine was that the dash panel uses a "Shared" "Choke" for both gauges.
A gauge "Choke" is really just a voltage reducer to knock the voltage to 6 volts (I don't know why they still run gauge at 6volts)
My "Choke" CRAPPED OUT, so I went extreme..... Black Taped over the 2 in the dash panel ....... then.....
Pulled the whole dash out, removed all the round vents and clock. Installed Stewart Warner Gauges in the 3 center holes.
Moved the clock to the far Right outside hole and put a Stewart Warner Fuel gauge in the far left outside hole. I did have to replace the Fuel tank sending unit to match the new gauge.

Or the smart easy way is to Junk Yard Safari a dash panel !!

Happy Trails CAPT