Dash gauges quit working

It's warm in Minnesota so back to the car. Pulled it out of the place it was parked for the winter (backyard) and moved to the front. Took a look at the instrument panel again. Forgot what I was looking at for repair so I had to come back and read my notes
No mice in the squirrel cage. I always take that apart first. Need to get a smaller flex line for my shopvac. Got some debris in the heater box so will clean that. Not sure if I'm going to rip the car all apart to do some major work on it. (wiring harness, clean up the car and document alot of the work) but I will be the first to admit I don't have a heated garage (which I really hope to rectify this summer) and in order to do that I need to finish up some woodworking projects in the garage. Plus I've got a stubborn Sport Trac that has a 5.0 installed, new exhaust but another wiring issue as it will not start that I'm working on. Plus the normal fixing of stuff breaking around the house. Busy summer. Fun times.

Oh. Forgot another fun component. After I was running the car I noticed the headlights had come on (without me turning on the switch). When I shut the car off they were still on. I had to go into the car turn the lights on and then back off and then they would turn off.

For the light switch, remove it (takes maybe 5 minutes working slow) and blast the snot out of it thru every opening with electrical contact cleaner. Operate the switch several times and blast it with contact cleaner again, and operate the switch several times. I use CRC brand contact cleaner which has a lubricant in it in addition to the cleaning chemicals.

Some other things. The ribbon on my instrument cluster has come apart in certain areas. Never noticed it before so don't know if it was a result of me taking it out or if this is the cause of the cluster failure. I've found a couple of IC's for around $100. Do I risk the ribbon being the problem and is there anyway to fix the ribbons? I also found someone on ebay selling a new set of gauges. They look really really cool but I think I would have to rebuild the existing cluster.

Ribbon. https://ibb.co/Z2DKPrH

Also reading my EVTM according to the manual if there is no IC illumination with parking lights on it says to check LB/R 19. What should be the voltage for this? Is this the 5 volt or should it be the normal 12 then to the IC voltage regulator?

https://ibb.co/album/w7RfQd

Cluster illumination is 12 for full brightness. Rheostat in light switch reduces this voltage to dim the cluster. IVR is only used for the oil press, fuel gauge, and temp gauge and has nothing to do with cluster illumination.

Breaks in the traces on the flexible plastic printed circuit can be fixed. I have done it several times on various cars. Just solder a piece of bare wire across the break.

Would like to find a solid state IVR... most of what I can find are for the earlier fords (1970's)... I did find one for a 74-86 mustang on blue oval industries but they are out of stock.  The IVR's listed for earlier years look the same and have the same style 9v battery type terminals. 

Would this one work?  Also what are they referring to regarding being properly grounded? This isn't just attached the same as the stock unit or does it require a ground wire to be added?

eBay IVR

That pic in your link looks like a old style mechanical / thermal failure prone IVR. those were simply 2 terminal devices. Electronic IVRs will need to be grounded, likely thru the metal case. If that IVR in the link is an electronic IVR built into one of the old style cases, it would need to be grounded thru the mounting bolt.

You can build your own solid state adjustable IVR for under $10 worth of parts if you have minimal soldering skills. Check the tech articles for info.

Thanks... was searching for a solid state ivr and I guess they slipped this on in on me

I did see your writeup and may go that route however if I can find one to purchase, that would be preferable.

Some other things.  The ribbon on my instrument cluster has come apart in certain areas.  Never noticed it before so don't know if it was a result of me taking it out or if this is the cause of the cluster failure.  I've found a couple of IC's for around $100.  Do I risk the ribbon being the problem and is there anyway to fix the ribbons?  I also found someone on ebay selling a new set of gauges.  They look really really cool but I think I would have to rebuild the existing cluster.

Ribbon.  https://ibb.co/Z2DKPrH

Also reading my EVTM according to the manual if there is no IC illumination with parking lights on it says to check LB/R 19.  What should be the voltage for this?  Is this the 5 volt or should it be the normal 12 then to the IC voltage regulator?

https://ibb.co/album/w7RfQd

As Jeff suggested, just solder a small piece of wire across the break in the ribbon. This will be much easier if you tin the wire first—be careful not to hold the soldering iron on there too long or you will melt the plastic backing.

Electronics stores, like Radio Shack or *sigh* the late Fry’s Electronics, sold a bottle of, essentially, liquid solder—powdered lead and silver in an alcohol-based solution. You spread that across a crack on a conductive surface, like a circuit board, and after the alcohol evaporated—Presto! Crack fixed, conductivity restored. I don’t know how well it would would work on a flexible surface though.

Over the years various users here have rebuilt their IP’s with newer gauges. I considered that when I was installing the LEDs last year. I searched through the old posts and from what I can tell, you need not only another IP to work on—so if you are unhappy with your creation you can put the OEM one back in; but also a fair amount of ingenuity to get the new gauges to fit properly; basic electrical knowledge to be able to wire it up; and a lot of patience. It seems like a LOT of work.

Back to this vehicle. Replaced the instrument cluster with a used one that was functioning and still the same issue. So likely not the IVR.

I also replaced the headlight switch so my headlights will go on and off properly and stay off when I start the car.

So back to the non-working gauges. Sounds like this goes through the IVR. I'm almost positive it's not this because I purchased a new one and the gauges didn't work. Replaced the entire IC which had a IVR and still not working.

So how do I test voltage going to the IVR or maybe a bad ground. The manual doesn't really say how to test voltage/ground to the IVR. I'm thinking I'm not getting any voltage to that.