amp gauge

[66T-Bird]

could someone simply tell me 0n a 1966 thunderbird were the needle is resting on the amp gauge? all of my gauges work and i have been told the amp really doesn't move much mine is always at dead center of D----C therefor i don't know if its working or not and should i be concerned or not Thanks Skip

[redstangbob]

I'd say your gauge is not working, they move quite a lot. Someone can correct me, I know they are different between years, but I think it was 65/66 were the same. If you decide to take it out, be sure to disconnect the battery, the amp gauge carries the full current of the battery! Good luck, Bob C

[john6t6]

Mine will move just off dead center towards the C side. Turning the lights on and off without the engine running causes the needle to move as well.

[TsNStangs]

Yeah, it should move some - my '66 would at start up, turning interior or exterior lights on/off, etc., pretty much anything that would affect the electrical draw. Sounds like yours is on the fritz.

[66T-Bird]

i appreciate all the replys but all i want to know is if the car is not on where is the needle sitting? Thanks Skip

[crazzzyjoey]

i appreciate all the replys but all i want to know is if the car is not on where is the needle sitting? Thanks Skip

Dead center if everything is off and there is no current draw on the battery.

[tbird]

Skip
The 66 Amp gauge should rest in the center as do the 64/65 gauges but the construction is completely different from 65-66. The earlier gauges had the complete electrical load going through the gauge other than the starter and couple of other major current draws this caused the gauge needle to deflect considerably as electrical loads turned on or off. The issue with this early design was that the high current loads running through the dash caused a number of cars to have dash fires, the harness plugs at the firewall also got very hot and in some cases melted to the point that the full battery current could short to the metal. The 64 was the worst for this some of the wiring sizes are larger in the 65 so it did not have as many problems.
In 66 they changed the wiring system added a fusible link at the battery and used a shunt type amp gauge, with this system the main load does not go through the gauge the wiring to it is quite light compared to the 64/65 the 66 gauge is actually installed in parallel with the main load so it only takes a sampling of the current flowing. With 45 years of corrosion in the wiring the resistance has increased as the current takes the easiest route this has caused most of the gauges to show very little movement in the needle today.
Many vehicles went over to the volt gauge shortly after this only one wire needed and does not need to be large no heat generated. hope burning up all this cyber space helps you out understanding the AMP GAUGE.

[TsNStangs]

Sorry Skip, I think we all thought you understood that the gauge should lie at dead centre when everything is off, being that the system would neither be charging ("C"), or discharging ("D").
You stated it wasn't moving much, and therefore wondered if it was working, hence our responses about what it SHOULD be doing.
Hopefully your question is cleared up now?

[66T-Bird]

thanks for all the help i'am very happy now knowing the actual workings of this guage so being i'am not having any electrical issues it must be working just fine Thanks again for taking the time to clear this issue up for me Skip

[dpranger]

With ref. to the tbird post of March 17, 2011 @ 11:24:

My old and beaten up shop manual shows (on p. 13-2) the charging schematic routing the full current load through the ammeter - which is contrary to the info given in the reply that indicates a shunted meter was used in '66. Which is correct?
(This wouldn't be the only error in the manual).

[sseebart]

With ref. to the tbird post of March 17, 2011 @ 11:24:

My old and beaten up shop manual shows (on p. 13-2) the charging schematic routing the full current load through the ammeter - which is contrary to the info given in the reply that indicates a shunted meter was used in '66. Which is correct?
(This wouldn't be the only error in the manual).

It's my understanding that the old-style, full-current load amp was used in '64, but dropped in subsequent years for the safer, shunted version, IIRC.

~Steve

[RAVEN]

Dpranger, what year is your car, and do you have the correct manual to your car?
Some errors exist in the MANUALS, but 64/65 was full current through the gage and shunted in 66.
In regard of this error, I am not aware.