THE23MAN

I have a 65, 289 A code 4spd fastback that I restored into a correct 66
Shelby GT350. However when turning the car on all the gauges go to
maximum! Ground issue? We have checked all the wiring and actually
have replaced the underwire dash harness with a brand new one and still
have the same issue. The 5 gauge cluster is an original set. Any
ideas?

 

Backyard Mechanic

"THE23MAN" <hddeuce00@nc.rr.com> wrote:

> I have a 65, 289 A code 4spd fastback that I restored into a correct 66
> Shelby GT350. However when turning the car on all the gauges go to
> maximum! Ground issue? We have checked all the wiring and actually
> have replaced the underwire dash harness with a brand new one and still
> have the same issue. The 5 gauge cluster is an original set. Any
> ideas?
>

With the senders disconnected?

And you see 5v average, {sweeping} at the Voltage reg?

With batt unhooked, OHM out one at sender connector, like the Oil Pressure,
work backwards.

--
Yeh, I'm a Krusty old Geezer, putting up with my 'smartass' is the price
you pay..DEAL with it!

THE23MAN

I do not understand your message. Could you please repeat as we are
desperate and cannot figure out what the issue may be. Thanks so much!

.boB

THE23MAN wrote:
> I have a 65, 289 A code 4spd fastback that I restored into a correct 66
> Shelby GT350.

And I have a 82 Bonneville that restored into a correct 64 GTO.

The gauges are really nothing more than an ohm meter. The sending unit is a
variable resistor.

There is a voltage regulator on the back of the gauge cluster that stabilizes gauge
voltage to a constant 5v. It looks kind of like a circuit breaker. Did you bypass
that during the re-wiring? Check and make sure that the gauges are only getting 5V.
If there is 12V, the regulator is bad.



--
..boB
On Order: 2006 FXDI, Red.
1997 HD FXDWG - Turbocharged Stolen 11/26/05 in Denver
1HD1GEL10VY3200010 CO License J5822Z
2001 Dodge Dakota QC 5.9/4x4/3.92
1966 Mustang Coupe - Daily Driver
1965 FFR Cobra - 427W EFI, Damn Fast.

THE23MAN

Yes we bought a new voltage reg (the small one that you referred to)
and still not working correctly! Any other ideas???

.boB

THE23MAN wrote:
> Yes we bought a new voltage reg (the small one that you referred to)
> and still not working correctly! Any other ideas???
>
Check it out to make sure it's working correctly. SHould have 12V in and 5V out.

Then check the gauge wiring. Make sure there's 5V into the gauge, and 5V out.

Remove a post from the gauge and see if there's a direct short to ground.
Sounds like there's a common ground wire that's shorting all the gauges at the same
time.

--
..boB
On Order: 2006 FXDI, Red.
1997 HD FXDWG - Turbocharged Stolen 11/26/05 in Denver
1HD1GEL10VY3200010 CO License J5822Z
2001 Dodge Dakota QC 5.9/4x4/3.92
1966 Mustang Coupe - Daily Driver
1965 FFR Cobra - 427W EFI, Damn Fast.