[EL70SS]

Hi folks,
My 70ss amp guage was not getting good connection to the printed circut and thus was not working. I decided to run a wire from the positive side of the gage(I hope positive is the right side post gage facing front) to the acc of the fuse box and one wire to a ground. I started the car and the gage moved and is now facing down to the ground. I did not remove the lead from the printed circut and am now worried that I blew the gage. Any insight on this? I'm not sure what went wrong and all the other gages are working well. Any help would be great!
Thanks

 

[John_Muha]

Hard to tell what may have happened. Isn't there ammeter wires tied to the junction block behind the battery and the other on the horn relay? I believe that's where they go.
Sounds like you tried to hook it up like an aftermarket voltmeter.

 

[Ark68SS]

You're not supposed to ground an ammeter--it causes a direct short. Maybe when you did this the gauge blew like a fuse & kept the wiring from toasting.

BL

 

[Steve S]

The factory amp gauge is really a voltmeter, it registers the voltage drop across a wire from the battery junction block on the radiator support to the horn relay. In other words one terminal of the amp gauge connects to the jucntion block and the other connects to the horn relay. You will have to remove your gauge (or pull the lens) and manually move the needle to the 12:00 o'clock position to get it to work right again, assuming that what you did, did not burn up the windings in the gauge. Most likely your original problem was blown etch on the circuit board. Every 70-72 gauge cluster I have restored had this problem. If you are good with a soldering iron and the damage is not too bad you can repair the etch by soldering on a jumper wire then sealing with rtv or epoxy to insulate. The other thing you can do if the damage is severe is to remove the two wires from the gauge connector, crimp on terminals and mount them directly on the gauge.
I highly recommend that you fuse the two wires under the hood at the horn relay and battery junction terminal with a 5 amp fuse on each. This will protect your gauge, circuit card and wiring.