67 Mustang - Most Gauges Don't Work

[jrandy]

Hey all,

I recently just picked up 67 Mustang with most of the gauges not working. I'm going to be replacing the IVR as this seems like most likely issue.

http://www.cjponyparts.com/mustang-...or-1967-1968-installation-instructions/a/357/

However, one thing that is throwing me off is that the only gauge that works is the fuel gauge (and it works very well for that matter).

Logic would assume that if the voltage regulator was broken, none of the gauges would work. However, this is new territory to me.

 

[cotten]

the fuel gauge doesn't require voltage. It only requires a solid chassis ground. 10-75 ohm signal from the fuel sender. Operates by the potential difference not voltage. All other gauges require voltage and sensor input. I think you are on the right track.

 

[jrandy]

Thanks for the response Cotten.

That makes a lot of sense. I'll get the IVR and see if that resolves the remaining gauges.

:beer:

 

[cotten]

Thanks for the response Cotten.

That makes a lot of sense. I'll get the IVR and see if that resolves the remaining gauges.

:beer:

I've noticed that to be the culprit with many of these cars.

 

[jrandy]

Well, on to step 2. I got the new voltage regulator and installed it today. None of the gauges worked, but more interestingly, the gas gauge stopped working.

I put the old regulator back in, and the gas gauge worked again. Nothing else was changed between the two.

Anyone have thoughts?

 

[cotten]

gauge fuses? Check for power against a chasis ground, not the wires. ohm out all connections.
http://averagejoerestoration.com/wp...m/1968-mustang-wiring-diagram-instruments.jpg

there's a link to a schematic.

Follow pin 39 through pin 30. check voltage between the 2 on the incoming plug. Verify ground on 57.

Do the dash lights work? Check all fuses box fuses.