87 GT, fixed temp gauge pegging issue, new switch, and I think I zeroed it correctly. Turn the key to on, SES light comes on & gauge doesn't move. Turn the car on to let it warm up, gauge sometimes moves but it jumps like in 1/4 inch increments (like the needle is being held up some place) and once I turn the car off to let it cool the gauge needle is still up saying its hot, again it hangs up in place. Also I had to put a drop of glue on the needle otherwise it would fall off. I don't know what to do especially because I have an overheating issue from blockage or WP. Please Help!!
thanks

Okay now the gauge doesn't move at all!! The needle sits on there fine and is at zero (100) but will not move. Now I am thinking it is the temp. gauge switch/sender but it is brand new and was working before I did the pegging gauge fix or the wires coming off the gauge are f'd. How do you test the gauge and wires/what is the grounding procedure?

With key on, ground each wire from the sending unit. The gauge should peg to the right when you ground it, and the light will come on when its' wire is grounded.

I stuck a paper clip in the connector and grounded each wire. This didn't do anything to the gauge or light. With the key on the SES light is always ON. The thing is it was working but the needle was getting hung up. After messing with the needle it does not get hung up anymore but now it doesn't move AT ALL. All connections should be good b/c it was working.

Did you carry out the fix for a pegging gage as per instructions on the fierosails.com site? The wiring diagrams provide good start on running down problems.
The prior advice on connecting the connector leads to ground will tell you if there is a problem wiht the sender/switch or elsewhere. If as you indicated, with the key in run/on, neither the gage or the coolant termperature switch reacted to the end of the connector contacts being grounded, this is an odd outcome. The 12 volt supply to both the gage and the temp light also supplies the tach, oil pressure gage, brake on lights etc. Are these working? If so, then in all liklihood you have the necessary 12 volts to the temp light and temp gage. So going to ground will cause them to react.
So, if grounding the connector contacts (the ones that plug into the temp switch/sender) don't cause either the gage or temp light to react, either both these components are shot or there is a wiring connection failure between the end of the connector
The wiring diagrams on fierosails.com should aid in tracking down the fault. Obviously you should revisit the wiring mods made to fix the gage pegging problem and make sure connections are good

Yes I used the fierosails.com instructions. I have checked my wiring at the gauge cluster and it was good but I can always recheck it. I tried grounding both wires that go into the temp. sender with no result. My TACH and OIL pressure gauges work fine. Like I said it was working, just the needle was screwed up so I messed with the needle a bit and now nothing! I will check my wires again but is there anything else that may cause this??
Thanks

quote Originally posted by goldiron: Did you carry out the fix for a pegging gage as per instructions on the fierosails.com site? The wiring diagrams provide good start on running down problems. The prior advice on connecting the connector leads to ground will tell you if there is a problem wiht the sender/switch or elsewhere. If as you indicated, with the key in run/on, neither the gage or the coolant termperature switch reacted to the end of the connector contacts being grounded, this is an odd outcome. The 12 volt supply to both the gage and the temp light also supplies the tach, oil pressure gage, brake on lights etc. Are these working? If so, then in all liklihood you have the necessary 12 volts to the temp light and temp gage. So going to ground will cause them to react. So, if grounding the connector contacts (the ones that plug into the temp switch/sender) don't cause either the gage or temp light to react, either both these components are shot or there is a wiring connection failure between the end of the connector The wiring diagrams on fierosails.com should aid in tracking down the fault. Obviously you should revisit the wiring mods made to fix the gage pegging problem and make sure connections are good