bop11

It is different if you have an ammeter than if you just have an indicator light.

clewi23

Hi. The temp gauge clicks all the way up when grounded, and moves back down a bit when the ground is removed. The fuel gauge does not move much, or very slowly, when grounded. I have checked the IVR and it is fine. The wiring is brand new and appears to work correctly. Do I need to replace the gauge?

bop11

I believe the early mustangs used a bi metal strip to move the needle. If grounding the sender wire at the gauge (yellow-white , i think) doesn't move the needle all the way up the bi-metal or the windings. There are no bearings. Note in the picture the needle has been bent out of the way. The white wire gets hot and causes the metal arm it is wound around to bend. Since the needle is attached to the free end of the arm it appears to rotate. Also note the hole at the upper right. It looks like there are gear teeth next to it. That is for adjustment. There is one at the lower left. One adjust the full stop and the other the empty stop.

bop11

Sorry, somehow lost the words doesn't move the needle all the way up the bi-metal or the windings are bad.

clewi23

Thanks again! Yea, I figured that out. You have been a great help and I am learning your way of giving information. I am also thinking I may have the wires backwards on the gauge. Easy first test...I have a wiring diagram, but on one schematic it shows the Yellow on the outside - toward sender - and on another page it has it on the inside - toward IVR. (of course the Black/Green is on the other post), I am narrowing this down! With YOUR help! You cannot believe how long I have been working on this car - weekends, evenings, etc., I am SOOO close! Thanks again! I gather from what you are saying is if it does not move correctly or adjust at all - I need a new gauge. As I have said, I have replaced about everything else....The temp gauge does respond to grounding, but does not go toward Cold as far as I would think after this test. I may just warm the car enough and see if it moves...or maybe I will just go for it and get both gauges if the Fuel one is bad...Again - thanks for your help! By the way, as per your input - the Alternator regulator is now wired correctly and the IVR has been replaced as it was bad. See ya!