halsted

Working on '65 coupe. Instrument panel lights, fuel gauge, oil gauge, and temprature gauge all don't work. Is it voltage regulator or fuse or ???. Any advice?

Cogtx

I had similar issues with my 67 coupe. No instrument cluster lights or gauges. First check for blown fuse and then you may have to replace the instrument cluster voltage regulator located behind the cluster itself.... http://johnsmustang.com/Parts/details-4152.html

Could also be a loose ground wire on back of cluster at the voltage regulator...try the fuses 1st and keep us posted...

halsted

The voltage regulator you speak of is not the one in the engine compartment? If not, can you describe where it's loated and what it looks like. Thanks

JamesW

CVU (Constant Voltage Unit) or IVR (Instrument Voltage Regulator) are the same thing. It is screwed to the back of your instrument panel. 12v in from the fuseblock , 5v out to the gages...

Possible causes:
- no 12v from the fuseblock to the IVR
- IVR bad (no 5v out)
- No Instrument Panel ground

Cogtx

check the link in my post above for a picture....then read what JamesW said....once you remove the instrument cluster, the cluster voltage regulator is attached to the back with (i think) one screw...you can't miss it...


Also, if you are handy with a soldering gun, this link will show you how to make a soild state regulator which is much more stable and last longer than the old fashioned ones...
http://www.allpar.com/history/mopar/electrical2.html

halsted

Thanks for the terrific posts, guys. I wll take down instrument panel and look for it although the last time I took off panel I had a hard time getting speedo cable back on. Not looking forward to doing that again. Will I be able to get this voltage regulator at local parts store or will be tough to get? Thanks again

JamesW

I don't know if local parts stores stock them anymore. You may have to order one from a speciality store like Mustang Plus, Texas Mustang, Mustang Depot, etc...

Re reading your post, you said not only the gauges but the panel lights don't work. The lights do not get their power from the IVR.... so it's more than likely the Instrument panel ground wire. There is a wire that hooks under the bolt of the IVR that runs to the center brace of the dash. This grounds the assembly. Check to see it is still in place and tight.

halsted

That is correct. When **** is pulled for lights, headlights come on, but instrument panel is dark.Thanks for the tip on the grounding wire. I will check that first. You sound knowledgeable on electronics as I am not, but I do have a meter. Is it possible to test the CVR to see if it is bad prior to replacing it? If so, could you explain it to me as you would to a child.

JamesW

If you pull the headlight switch and the headlights come on but the instrument panel is dark, then it is not the CVR. The power to the lights does not go through the CVR. Only the Oil, Temp, and Gas gages. If the dash lights AND the gages don't work, then it's definately a grounding problem..

Try pulling your dash out a little, unhooking the speedo, and pull it forward a few inches. Take a piece of wire and ground the metal case on the back to the car ground and hit the hit the lights...see if that works.

halsted

I did have to take panel off once before to replace ignition switch, maybe I knocked ground wire off. Also, not all the gauges don't work. Only, temp, fuel, and oil. Speedo works, but that is expected since it is mechanical, and alternator seems to work. Does that change things? Thanks