71 dash: wiring diagram

[GER_ONE]

Hey all,

please welcome a new member of this community. Just bought a 1971 429 Tbird - very proud of it!

Unfortunately the dashlight wouldn't work and I am trying to fix it without spending hours and hours finding out about the wires. Does anybody of you have a wiring diagram which he could send me? I do have the Repair Manual, but unfortunately there is no exact diagram in it.

You would be of great great help!

Thank you in advance,
Seb

 

[tbird5866]

If the dash lights do not work, you probably have one of two problems. One - the fuse is blown. Two - you have a bad reostat in the headlight switch. If you have power coming from the fuse with the dashlight switch turned on, go to the headlight switch. Probably replace it or rewire to do away with the dimmer. (leaving the dash lights to come on with the tail lights.)

 

[warrior74z]

Hi T Bird friends!
I also have an electrical problem with a '71 T Bird. The fuel, oil pressure, temp gauges might work this week, and not the next. Amp gauge always works. Sometimes I can repeatedly turn the ignition switch on and off and get the gauges on. Lately no luck.
I have read somewhere that the '71 was the first year to have a shunt in the gauge electrical system and that this could be the problem. Any ideas guys? Have disconnected all wire plugs and cleaned and inspected and disconnected all grounds and cleaned and inspected. If the shunt is suspect, where is it located? Car was bought by my dad in '71 and has 79,xxx documented miles.
Any help would sure be appreciated.
Thanks
Barron Cooley
Anderson, SC

 

[tbird5866]

Normally, trouble with those three instruments is caused by a bad "instrument voltage regulator". Located somewhere behind the instruments, this devise reduces the voltage to the gauges to an average of five volts. Yours may not be grounded properly or it may need to be replaced. Ford part number is C7SZ-10804-A used on 1967 thru 1971 Thunderbirds. Seems I recall those instruments come out very easily. Knowing what to look for may help you.

 

[warrior74z]

Thank you Harley for such a prompt reply. I will check it out and get back with you. Your knowledge is priceless!
Barron