SAAC Forum

The Cars => 1967 Shelby GT350/500 => Topic started by: greekz on June 30, 2026, 06:07:06 PM

Title: Gauges Quit Working
Post by: greekz on June 30, 2026, 06:07:06 PM
While driving my '67 GT-350 last Sunday my temperature and fuel gauges stopped working.  Everything else works but the gauges.  I am thinking the IVR died.  Any simple checks before I remove the cluster?

Thanks,

Greek
Title: Re: Gauges Quit Working
Post by: roddster on July 01, 2026, 12:31:31 PM
Yep, pulling the cluster is not easy.  Check for voltage at either the temp sensor wire or the fuel pick-up wire. 
  Tough choice to either use an OEM style voltage limiter or the new electronic type.
Title: Re: Gauges Quit Working
Post by: greekz on July 01, 2026, 01:49:03 PM
Thanks for the tip.
Title: Re: Gauges Quit Working
Post by: greekz on August 11, 2026, 04:11:19 PM
I finally had time to investigate the gauge problem.  I found the ground wire that plugs in the connector located on the IVR mounting post was half way out.  Pushed it all the way in and tried the gauge.  It worked, but pulsed slightly.  I removed the wire and cleaned the spade and brass connector, also cleaned the connections on the IVR.  After reconnecting all connections and testing, the fuel gauge worked with no pulsing.  I then started her up and both fuel and temperature worked perfectly.  Next test will be a drive this Sunday.  Hopefully, both gauges will work as they should.
Title: Re: Gauges Quit Working
Post by: roddster on August 18, 2026, 12:24:14 PM
The gauges work from a 4.5 to 5.0 supply from the IVR.  To cut it down to that, the 12 volts is "pulsed" in the IVR circuitry. The electronic (new age) IVR supply is constant (4.5 to 5.0) volts, but it does not pulse.
Title: Re: Gauges Quit Working
Post by: greekz on August 18, 2026, 05:20:31 PM
Drove my car on Sunday and both gauges worked as they should.  It seems the terminal cleaning did the trick.  I hope this helps anyone who might encounter the same problem other than the IVR failing.