I noticed this morning on my way to work that I was out of gas but yesterday I had plenty. I put $25 in my tank and went on my way realizing that only got me 1/4 tank when usually that more like 1/3 tank. Then I realized the temp guage was hardly moving and the oil press was way low!! I'm thinking it's a ground issue.. Any other ideas or thoughts on where to start?? Tomarow I'll pull the cluster and clean all terminals and contacts. Also.. What wire could I tap into to add another ground??

 

When all the gauges start to go "weird" on you at the same time it's usually the ICVR (instrument cluster voltage regulator).

 

Sound good to me.. Lol

Where is it and how do I test it??

 

It's located behind the instrument cluster, test with a voltmeter, it should pulsate 5v every second or so.

 

Also if you want to add a ground - after you pull the gauge cluster out, you should see where a ground is attached to a support. I'm not describing it too well, but I think you will see it. Put a ring terminal on a wire and add it to the one already bolted down, and you are all set.

 

1967/72 F100/350: There are three different ICVR's used on these trucks, because...1970/72's have printed circuit boards. 1967/69's do not.

The printed circuit boards used in 1970, are 1970 only, as is the ICVR.

1971/72's use the same boards / Note: 1970/72: The boards are specific to: With oil/amp gauges / With oil/amp warning (idiot) lights.

1967/69 F100/350: C6DZ-10804-A .. ICVR = Instrument Cluster Voltage Regulator (Motorcraft GR-510) / Obsolete

1970 F100/350: C9AZ-10804-A .. ICVR (Motorcraft GR-512) / Obsolete

1970/72 F100/350: D1AZ-10804-A .. ICVR (Motorcraft GR-513) / Available from Ford.

1967/69: The ICVR bolts to the back of the instrument cluster.

1970/72: The ICVR snaps onto the printed circuit. Be very careful when removing the ICVR, if you tear the printed circuit, you'll be huntin' for another.

Available from autoparts stores, but make sure to take the original with you, so you can match it up.

Besides these 3 ICVR's, there are 5 more used on other FoMoCo vehicles.