Persistant gauge problem 70 Mach 1

[04mustang70]

I have a 1970 Mach 1. This is the second post but the first post didn't fix the problem. I installed LED's in my instrument cluster. When I got done everything worked except the Fuel, oil and Temp gauges. The gauges worked fine before installing the LED's. First thought was the IVR. Bought a new one. Gauges still didn't work after installation. I am sure the IVR is good because when I put 12v to the ignition side of it and ground the body I get a good pulsing out of the remaining terminal. I checked the plug that goes to the back of the instrument cluster. All the appropriate terminals are either getting power or are grounding out. The gauge cluster is properly grounded also. I took the LED's out to see if that was the problem but no still no gauges. Everything else works (turn signals, highbeam indicator and dash lights). I was wondering if I could have fried anything while poking around with the test light. What are my next options? I really don't think all three senders fried at once. Could the gauges themselves fry out somehow? If so how do I test those? I had to fry somthing that Iv'e been over looking. This is really getting to me as I have had the gauge cluster out like fifty million times already. I'm at my wits end over this problem that shouldn't be that difficult. Thanks in advance to all that respond.

 

[palerider94]

Sure sounds like the IVR. I doubt you fried all 3 gauges. I've had mine out on both my 70s a bunch of times - on both cars did have problem initiallly with popping a fuse when reinstalling -something on circuit board was touching metal causing short. Also on back of IVR hookup from factory there was a plastic cover over IVR terminals to keep it from touching something and grounding out. May want to cover terminals with tape. Also try and see if they work without mounting cluster - just to see if something is grounding out. My want to consider changing out printed circuit board as a last resort. Also may want to try attached site - only 69/70 owners - maybe someone can give you some other ideas. Good luck.

1969 Mustang Supersite Web Forums - Powered by vBulletin

 

[04mustang70]

After digging around on the forum and trying out what I found. I now know what people mean by centering the gauges. All the gauges were not centered and grounding out. They work great now. Thanks for your help Till next time

 

[tx65coupe]

Make an electronic IVR. Those replacement ones are crap. I have 3 of them that are crap. My original one works the best.

We made one with parts from Radio Shack for about 7 bucks. We actually housed it inside one of the old cases.

You just need the instrument cluster voltage regulator to put out 5 volts I think it is. It could be different for your later model car though.

Instrument Panel Function Electrical Basics - Mustang & Fords Magazine

Here is a thread I started on another forum about it.

modifing the CVR - Page 2 - MustangForums.com