1965 instrument voltage regulator
 

I have a new instrument voltage regulator to install on my 65, can't find it anywhere near the battery in the engine bay. Is this under the dash somewhere, if so, how hard is it to get at?

Thanks, Watermelon Jack

It's under the dash above and to the right of the speedometer. Section 15 of the shop manual has the details. They tell you to remove the speedometer, but if you don't mind some skinned knuckles, you can replace it by removing the clock console (described in the same section). Once you have dropped the clock console, the regulator is to the left. Not easy to get to, but can be done.
Hope this helps
Terryw
64HT

thanks, it still sounds like a bit of work, so I hope it is worth it.

While it's awkward, it's not too difficult and worth it if your gauges are incorrect or not working.
Terry64HT

Thanks, I don't like the way the ammeter keeps bouncing around and I don't trust the oil gauge as it reads too low as there is nothing wrong. I found the information in the manual as you described. Time to lose some flesh.

1965 Town Landau 70K original miles 99% fully loaded, all original

Others in my barn, 1969 MGB GT rolling restoration but otherwise 90% done, have participated in All-British runs for over the past 10 years,1969 Mustang Fastback Restomod 70% complete, someday she will fire up.

:driving

The voltage regulator won't fix the bouncing ammeter, that's probably a ground issue. The regulator supplies 5 volts to the oil, gas and heat gauges. If only one is reading odd, chances are it's not the regulator.
Good luck
Terry64HT

So I suspect the grounding issue is then related to somewhere on the dash? I was hoping the solid state version of the constant voltage regulator would cure some things. I have the wiring diagram manual , but where do I start looking for the grounds? British cars are notorious for the same problems (Lucas, Prince of Darkness)

By ground, I meant the one from the battery to the frame and then to the engine block. I'd take it off and clean the area at the frame. The original ones were one piece from the battery to the block with a lug in the middle for the frame, but many have been replaced with two different wires. Oil and dirt gets between the lugs at the frame, making a poor ground.
I think in 65 power went from the alternator to the ammeter and then to the lights and ignition switch. Once power comes out of these, there's a ground for each item. It's not likely that any one thing would draw enough power to make the ammeter bounce in big swings.
Terry64HT

Thanks, I will start in the engine bay and check everything. I hate the idea of disturbing the dash. Do you think teflon tape on the oil pressure sender would interfere with the grounding for that gauge? The manual says to use "an electrically conductive sealer". I installed an new oil pressure sender when I put on a new fuel pump. I do have a new wire for the sender to install as the original is a little shady.

The oil pressure and temp gauges are grounded through the threads. Teflon tape would probably interfere, but the threading action probably has cut the tape enough for a circuit. You can check the ground resistance between the sensor just above the threads and the block. Teflon tape isn't supposed to seal a threaded connection, it's lubricant.
I mentioned a poor ground, but it wouldn't hurt to check the positive connections at the solenoid, battery and disconnect through the firewall. I recall that this connection sometimes corrodes.
Terry64HT

same issue with the constant voltage relay
 

I have a 65 bird with non working fuel gauge and temp gauge. I'm trying to feel for the existing voltage relay, and have removed the clock housing. Is the relay on the front or the side of the speedometer? I haven't had any luck using a mirror or feeling with my fingers. Any help would be greatly appreciated!

If your gas gauge works then the voltage regulator works.

Ground out the sender wire at the temperature sender- it should send the gauge full hot. Same with the fuel sender.

I believe the regulator was originally mounted to the back of the speedometer housing near the clock end, but if it was ever replaced was often moved to a more convenient location. To complicate things a bit more, it may even have been replaced with an aftermarket one that might not even look the same. Some of the earlier replacements were just a bare board just over an inch square. All you can do is fish around a bit. To make it even more fun, if you use a mirror with a metal frame, it will keep getting sucked to the speaker magnet....
Wish I could be of more help. I thought I had photos of my replacement, but they seem to have disappeared.
Terry
64HT

Did you ever sort out the instrument voltage regulator problem? Things kind of died a few weeks ago.
Terry
64HT

I finally sorted out my problems with the gauges - I took the speedometer housing off, and the gauge cluster as well. The old voltage regulator under the speedometer was defective, and I could never have gotten it off, and the new one installed with the wires without having the gauge cluster out of the way. The second issue I had was self inflicted - when I was reassembling the dash after getting the vinyl recovered, I installed one of the leads on the instruments backwards. The lugs on the back of the gauge clusters are not marked for hot or ground, and the electrical diagram isn't too clear on it. So I put the gauge cluster on the test bench and tested each gauge, and marked the back of the housing with a Sharpie
as to the color of wire and also which lug is hot. After reassembling the dash (again!!!) everything works as designed.